Long commit subjects and bullets are hard to read in narrow terminals and
mailed logs. Contributors using `.githooks` via core.hooksPath now get an
automatic guard in addition to the two-file pre-commit cap.
- Add `.githooks/commit-msg` to fail when any message line exceeds 80 chars
- Skip length checks while `.git/MERGE_HEAD` exists for merge commits
- Sync AGENTS.md, README.md, CONTRIBUTING.md, and commit.prompt.md
Spell out that SPDX tags must use native comments (`#` in code and TOML,
HTML comments in Markdown/Quarto) and call out formats like JSON that cannot
carry in-file blocks.
- Add an SPDX section with concrete examples and the strict-JSON caveat.
Explain next to the one-file workflow that message depth should follow patch
size—grouped bullets on large or multi-concern commits.
- Adds one bullet under coding rules pointing readers at `.github/prompts/commit.prompt.md`.
Replace outdated badges and roadmap prose with the current 2.0 focus areas,
installation notes, and pointers to AGENTS.md. Rewrite CONTRIBUTING as a
concise fork/test/layer-contract checklist aligned with the repo layout.
- README: drop stale Travis/Gitter stack; document legacy module caveat
- CONTRIBUTING: remove Quarto front matter; link architecture_layers checker
Jukka Aho