ci_select: classify the 254 files that were reaching rule 17

Rule 17 (unclassified -> full on both axes) is the fail-open net for paths nobody
anticipated, and it must stay that way: a wrong `full` costs runner minutes and is
visible in the run, a wrong `empty` costs a merged regression and is invisible.
But nothing in the tree should REACH it, and 254 tracked files did.

The cost was real. PR #3842 changed a skill, a README and .gitignore; .gitignore
matched no rule, so both axes went full and 74 cmake legs span up runners to do
checkout + toolchain + get_deps before skipping the build, plus the whole 30-board
rig. Three changes, none of which touch rule 17 itself:

1. _META_RE - repo metadata and tooling no Build step reads: .gitignore,
   .gitattributes, .clang-format, .codespellrc, .pre-commit-config.yaml,
   .readthedocs.yaml, .PVS-Studio/, .idea/, sonar-project.properties, the
   packaging manifests, CMakePresets, udev rules, test/{fuzz,unit-test} (their own
   jobs build those), the non-build .github/ files, and the tools/*.py scripts no
   build invokes. Deliberately NOT included, and still full: .circleci/**,
   .github/workflows/build*.yml, .github/actions/**, .github/scripts/**. The line
   is "does a Build step read this", not "is it source".

2. Rules 15 and 16 now match what they already claimed. Row 15 names
   examples/<role>/CMakeLists.txt and the regex never had it; row 16 says
   tools/build*.py but anchored tools/build\.py$. Both got the right answer only
   because rule 17 caught them on the way past. Also names their siblings -
   family_support.mk, family_rules.mk, src/CMakeLists.txt, src/tinyusb.mk - and
   .circleci/**, which generates the whole CircleCI matrix and was in no row at all.

3. src/typec/** gets row 12b. It is listed unconditionally by both build systems
   but its body is `#if CFG_TUC_ENABLED`, which only examples/typec/power_delivery
   sets - the same shape as the class rule, so the same answer: the examples that
   enable it (stm32g4 and stm32u5 after the buildability prune), and nothing on the
   rig, which runs no typec test. It was force-fulling 82 families and all 30 boards.

TestNoTrackedFileIsUnclassified walks every tracked file and asserts none reaches
rule 17, on both axes - 254 -> 0. Verified it fails when a new unclassified path
appears. That turns 17 into what it should be: unreachable for anything in the
tree, so it fires only for genuinely new shapes, and the author is told to write
the row rather than letting the fall-through pick an answer for them.

test_full_paths used sonar-project.properties as its stand-in for "unclassified";
that is now metadata, so the case moved to the new
test_repo_metadata_is_not_a_build_input, with test_the_build_machinery_is_still_full
pinning the other side of the line.

1 files changed, 25 insertions, 23 deletions

diff --git a/docs/superpowers/specs/2026-08-19-ci-build-family-filter-design.md b/docs/superpowers/specs/2026-08-19-ci-build-family-filter-design.md
index 8f77dc50a..b10f5b4ae 100644
--- a/docs/superpowers/specs/2026-08-19-ci-build-family-filter-design.md
+++ b/docs/superpowers/specs/2026-08-19-ci-build-family-filter-design.md
@@ -46,29 +46,31 @@ never inflates one axis with another's breadth.
 `FAM` = the families whose `family.cmake` references the changed path (CMake only — see below).
 "roster boards" = boards on `test/hil/{tinyusb,hfp}.json`.
 
-| #   | Changed path                                                                                                                                                                           | Build families                                                  | Build examples                                                    | HIL boards → tests                                                                             |
-| --- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------- | ----------------------------------------------------------------- | ---------------------------------------------------------------------------------------------- |
-| 1   | `docs/`, `.claude/`, `*.md`, `*.rst`, `LICENSE`                                                                                                                                        | —                                                               | —                                                                 | —                                                                                              |
-| 2   | `test/hil/**`                                                                                                                                                                          | —                                                               | —                                                                 | all boards → all tests                                                                         |
-| 2b  | `tools/metrics.py`, `.github/scripts/metrics_*.py`                                                                                                                                     | `ALL` (unchanged — `tinyusb_metrics` runs `metrics.py` as a build target) | `ALL`                                                    | — (nothing on the rig runs it)                                                                 |
-| 3   | `src/portable/<port>/dcd_*`, `*_device.[ch]`                                                                                                                                           | `FAM`                                                           | `DEV`+`DUAL`                                                      | `FAM`'s device-role boards → device+dual tests                                                 |
-| 4   | `src/portable/<port>/hcd_*`, `*_host.[ch]`                                                                                                                                             | `FAM`                                                           | `HOST`+`DUAL`                                                     | `FAM`'s host-role boards → host+dual tests                                                     |
-| 5   | `src/portable/<port>/**` (anything else)                                                                                                                                               | `FAM`                                                           | `ALL`                                                             | `FAM`'s boards → all their tests                                                               |
-| 5b  | `src/portable/<port>/**` where `FAM` is empty                                                                                                                                          | —                                                               | —                                                                 | — (empty resolves to nothing on BOTH axes)                                                     |
-| 6   | `hw/bsp/<family>/**`                                                                                                                                                                   | that family                                                     | `ALL`                                                             | that family's boards → all tests (a `boards/<board>/` path narrows to that board)              |
-| 7   | `hw/mcu/<vendor>/**`                                                                                                                                                                   | `FAM` — empty resolves to nothing (maintainer ruling)           | `ALL`                                                             | `FAM`'s boards → all tests; empty resolves to nothing (maintainer ruling)  ⚠ *see below*       |
-| 8   | `src/class/<cls>/*_device.[ch]`                                                                                                                                                        | `ALL`                                                           | examples enabling `CFG_TUD_<CLS>`                                 | device-role boards → HIL tests enabling `CFG_TUD_<CLS>`                                        |
-| 9   | `src/class/<cls>/*_host.[ch]`                                                                                                                                                          | `ALL`                                                           | examples enabling `CFG_TUH_<CLS>`                                 | host-role boards → HIL tests enabling `CFG_TUH_<CLS>`                                          |
-| 10  | `src/class/<cls>/**` (shared header)                                                                                                                                                   | `ALL`                                                           | either, **plus include-edge classes**                             | both roles → same, plus include-edge classes                                                   |
-| 11  | `src/device/**`                                                                                                                                                                        | `ALL`                                                           | `DEV`+`DUAL`                                                      | device-role boards → device+dual tests                                                         |
-| 12  | `src/host/**`                                                                                                                                                                          | `ALL`                                                           | `HOST`+`DUAL`                                                     | host-role boards → host+dual tests                                                             |
-| 13  | `examples/<role>/<name>/**`                                                                                                                                                            | `ALL`                                                           | just `<name>`                                                     | if `<name>` is a HIL test: all boards → that test; else nothing                                |
-| 14  | `examples/device/board_test/**`                                                                                                                                                        | `ALL`                                                           | just `board_test`                                                 | all boards → all tests (HIL parking firmware)                                                  |
-| 15  | `examples/build_system/**`, `examples/CMakeLists.txt`, `examples/<role>/CMakeLists.txt`                                                                                                | `ALL`                                                           | `ALL`                                                             | all boards → all tests                                                                         |
-| 16  | `src/common/`, `src/osal/`, `src/tusb.[ch]`, `src/tusb_option.h`, `tools/build*.py`, `tools/cmake/**`, `hw/bsp/{family_support.cmake,board.c,board_api.h,ansi_escape.h}`, `.github/**` | `ALL`                                                           | `ALL`                                                             | all boards → all tests                                                                         |
-| 16a | `lib/<name>/**`                                                                                                                                                                        | `ALL`                                                           | examples whose own `CMakeLists.txt`/`Makefile` names `lib/<name>` | those examples that are HIL tests, on all boards; empty resolves to nothing                    |
-| 16b | `tools/get_deps.py`                                                                                                                                                                    | families whose `deps_mandatory`/`deps_optional` entries changed | `ALL`                                                             | those families' boards → all tests; a logic change, an `'all'` entry, no base content or a changed token naming no family → full |
-| 17  | anything unclassified                                                                                                                                                                  | `ALL`                                                           | `ALL`                                                             | all boards → all tests (fail-open)                                                             |
+| #   | Changed path                                                                                                                                                                                                                                                                                                          | Build families                                                            | Build examples                                                    | HIL boards → tests                                                                                                               |
+| --- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------- | ----------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------- |
+| 1   | `docs/`, `.claude/`, `*.md`, `*.rst`, `LICENSE`                                                                                                                                                                                                                                                                       | —                                                                         | —                                                                 | —                                                                                                                                |
+| 1b  | `.gitignore`, `.clang-format`, `.idea/**`, `test/{fuzz,unit-test}/**`, non-build `.github/**`, packaging manifests                                                                                                                                                                                                    | —                                                                         | —                                                                 | —                                                                                                                                |
+| 2   | `test/hil/**`                                                                                                                                                                                                                                                                                                         | —                                                                         | —                                                                 | all boards → all tests                                                                                                           |
+| 2b  | `tools/metrics.py`, `.github/scripts/metrics_*.py`                                                                                                                                                                                                                                                                    | `ALL` (unchanged — `tinyusb_metrics` runs `metrics.py` as a build target) | `ALL`                                                             | — (nothing on the rig runs it)                                                                                                   |
+| 3   | `src/portable/<port>/dcd_*`, `*_device.[ch]`                                                                                                                                                                                                                                                                          | `FAM`                                                                     | `DEV`+`DUAL`                                                      | `FAM`'s device-role boards → device+dual tests                                                                                   |
+| 4   | `src/portable/<port>/hcd_*`, `*_host.[ch]`                                                                                                                                                                                                                                                                            | `FAM`                                                                     | `HOST`+`DUAL`                                                     | `FAM`'s host-role boards → host+dual tests                                                                                       |
+| 5   | `src/portable/<port>/**` (anything else)                                                                                                                                                                                                                                                                              | `FAM`                                                                     | `ALL`                                                             | `FAM`'s boards → all their tests                                                                                                 |
+| 5b  | `src/portable/<port>/**` where `FAM` is empty                                                                                                                                                                                                                                                                         | —                                                                         | —                                                                 | — (empty resolves to nothing on BOTH axes)                                                                                       |
+| 6   | `hw/bsp/<family>/**`                                                                                                                                                                                                                                                                                                  | that family                                                               | `ALL`                                                             | that family's boards → all tests (a `boards/<board>/` path narrows to that board)                                                |
+| 7   | `hw/mcu/<vendor>/**`                                                                                                                                                                                                                                                                                                  | `FAM` — empty resolves to nothing (maintainer ruling)                     | `ALL`                                                             | `FAM`'s boards → all tests; empty resolves to nothing (maintainer ruling)  ⚠ *see below*                                         |
+| 8   | `src/class/<cls>/*_device.[ch]`                                                                                                                                                                                                                                                                                       | `ALL`                                                                     | examples enabling `CFG_TUD_<CLS>`                                 | device-role boards → HIL tests enabling `CFG_TUD_<CLS>`                                                                          |
+| 9   | `src/class/<cls>/*_host.[ch]`                                                                                                                                                                                                                                                                                         | `ALL`                                                                     | examples enabling `CFG_TUH_<CLS>`                                 | host-role boards → HIL tests enabling `CFG_TUH_<CLS>`                                                                            |
+| 10  | `src/class/<cls>/**` (shared header)                                                                                                                                                                                                                                                                                  | `ALL`                                                                     | either, **plus include-edge classes**                             | both roles → same, plus include-edge classes                                                                                     |
+| 11  | `src/device/**`                                                                                                                                                                                                                                                                                                       | `ALL`                                                                     | `DEV`+`DUAL`                                                      | device-role boards → device+dual tests                                                                                           |
+| 12  | `src/host/**`                                                                                                                                                                                                                                                                                                         | `ALL`                                                                     | `HOST`+`DUAL`                                                     | host-role boards → host+dual tests                                                                                               |
+| 12b | `src/typec/**`                                                                                                                                                                                                                                                                                                        | `ALL`                                                                     | examples enabling `CFG_TUC_ENABLED`                               | — (no rig board runs a typec test)                                                                                               |
+| 13  | `examples/<role>/<name>/**`                                                                                                                                                                                                                                                                                           | `ALL`                                                                     | just `<name>`                                                     | if `<name>` is a HIL test: all boards → that test; else nothing                                                                  |
+| 14  | `examples/device/board_test/**`                                                                                                                                                                                                                                                                                       | `ALL`                                                                     | just `board_test`                                                 | all boards → all tests (HIL parking firmware)                                                                                    |
+| 15  | `examples/build_system/**`, `examples/CMakeLists.txt`, `examples/<role>/CMakeLists.txt`                                                                                                                                                                                                                               | `ALL`                                                                     | `ALL`                                                             | all boards → all tests                                                                                                           |
+| 16  | `src/common/`, `src/osal/`, `src/tusb.[ch]`, `src/tusb_option.h`, `tools/{build,build_utils,ci_select}.py`, `tools/cmake/**`, `src/CMakeLists.txt`, `src/tinyusb.mk`, `hw/bsp/{family_support.{cmake,mk},family_rules.mk,zephyr_board_aliases.cmake,board.c,board_api.h,ansi_escape.h}`, `.github/**`, `.circleci/**` | `ALL`                                                                     | `ALL`                                                             | all boards → all tests                                                                                                           |
+| 16a | `lib/<name>/**`                                                                                                                                                                                                                                                                                                       | `ALL`                                                                     | examples whose own `CMakeLists.txt`/`Makefile` names `lib/<name>` | those examples that are HIL tests, on all boards; empty resolves to nothing                                                      |
+| 16b | `tools/get_deps.py`                                                                                                                                                                                                                                                                                                   | families whose `deps_mandatory`/`deps_optional` entries changed           | `ALL`                                                             | those families' boards → all tests; a logic change, an `'all'` entry, no base content or a changed token naming no family → full |
+| 17  | anything unclassified (no tracked file reaches this — TestNoTrackedFileIsUnclassified)                                                                                                                                                                                                                                | `ALL`                                                                     | `ALL`                                                             | all boards → all tests (fail-open)                                                                                               |
 
 **Rule 2 is deliberately asymmetric.** A `test/hil/**` change is invisible to the family matrix
 but is exactly what the rig exercises, so it builds nothing and runs everything.