[siracozmen01]

Problem

.github v0.0.48 adds the family's tools/tidy_filter.sh, which prints clang-tidy's header filter for a build tree, and v0.0.50 and v0.0.51 add a conventions rule on how state a caller holds is checked (Rawframe-Project/.github#119 and Rawframe-Project/.github#120). This repository lacks it, carries an older docs/internals/maul-conventions.md, pins the reusable workflows at v0.0.42 and v0.0.45, and builds the filter itself in two places.

Change

• The family files are synced to v0.0.51 with family_sync.py --write: tools/tidy_filter.sh is added, and docs/internals/maul-conventions.md gains the rule that every clang-tidy call takes its header filter from it and the rule on state a caller holds. AGENTS.md lists tidy_filter.sh among the shared files.
• Every reusable workflow and the docs-check action are pinned at 972ea41c6abf2652d3b067e57bf0713f1661cf0e # v0.0.51. Between the old pins and v0.0.51 only pr-title.yml changed among the workflows, and its old pin, v0.0.45, already had that change.
• ci.yml's clang-tidy step and tools/check.sh's tidy() set filter=$(tools/tidy_filter.sh <tree>) on a line of its own, so a tree without the cache entry stops the step instead of tidying with an empty filter, and pass --header-filter="$filter". tools/check.sh's own header_filter() is gone. A changed header still tidies every source.

Verification

• family_sync.py --check from v0.0.51 reports 0 differences.
• In a fresh clone of this branch, with only a header changed (return value == value; planted in src/bits.h), tools/check.sh changed fails on misc-redundant-expression in src/bits.h, and the ci.yml step's commands report it on the Release and Debug presets. tools/tidy_filter.sh on a tree whose cache lacks the entry exits 1.
• tools/check.sh changed passes on the clean branch, and shellcheck -S warning is clean on tools/check.sh and tools/tidy_filter.sh.

Closes #261

[siracozmen01]

Review at 56ee171. No changes needed. Read, not run. CI is green at this head.

• The two assignments. Neither is local x=$(...), and neither is inside an if condition, so a failure of the script stops the run.
  • In ci.yml's clang-tidy step, filter=$(tools/tidy_filter.sh "out/tidy-$build") is a plain statement inside the for build loop, after the configure. The job's default shell is bash (ci.yml:32), which GitHub runs with -e, and errexit stays active in a for body.
  • In tools/check.sh, tidy() declares local build filter on its own line, then assigns filter=$(tools/tidy_filter.sh "$out/check-tidy-$build") as a plain statement, under set -euo pipefail (check.sh:32). tidy is called in the body of an if, not its condition, so errexit is not suspended. header_filter is gone.
• The header-only rule is kept. The changed tier still sets headers=1 for a changed src/*.h (not below src/) or include/*.h, and then tidies src/*.c whole, as before. This PR does not touch that loop.
• Family files. tools/tidy_filter.sh is d61928e and docs/internals/maul-conventions.md is 80f34b2, the canonical blobs at 972ea41. AGENTS.md lists tidy_filter.sh after run_quarantine.sh, and no other word of the line changed.
• Pins. All seven .github references are the full 972ea41 sha: changes, docs-check, zizmor, cpp and cache-prune in ci.yml, plus pr-gate.yml and pr-title.yml.
• ci: is right at 1.x. Nothing a program sees changes, so no release follows.