docs: keep only the traps in CLAUDE.md

[omartelo]

CLAUDE.md is injected into every prompt, so anything in it that the code says better is a cost paid per session. This is a pass over the whole file with one question per line: what breaks if nobody knows this?

Out

• Self-update and No AppImage — decision history. It lives in internal/appupdate and docs/chromium-shell.md, and nothing breaks by not knowing it.
• Windows / macOS roadmap — code signing, winget, .dmg/Homebrew are issues, not ceilings. What breaks code stayed: cmd.exe as the shell, a GUI build with no console (so diagnostics only reach the log file), unsigned binaries.
• Release fan-out, job by job — release.yml says it. One sentence now, keeping the trap: the version is injected into nfpm.yaml, never hand-edited there.
• Terminal I/O transport — already in Stack. Only the fallback behaviour survives, which is the part that isn't obvious.
• "Frontend in isolation" — duplicated the Local Gate line above it.
• xterm / CodeMirror detail in the Stack bullet — frontend/CLAUDE.md covers it and loads whenever that directory is touched. The bullet points there now.

In

• docs/hooks/ as a cross-repo contract. It declares itself contract-first, and the other side ships in omartelo/lich-plugin. Changing an endpoint or payload breaks a repo this one cannot see, and the handler gives no hint.
• CHANGELOG entry in the same PR as the user-facing change. The release notes are read from [Unreleased], so an entry written later missed its release. The convention was already in the history, just not written down.
• The criterion itself, in the Known Ceilings intro — a bullet earns its place by naming a trap the call site never shows. The next one written there has a bar to clear.

The api-types.ts rule stayed on the root on purpose: it breaks in the backend direction (touch a Go struct's JSON tags), and frontend/CLAUDE.md never loads on that path.

Test plan

Docs only — no code touched, so the gate has nothing to run. What was verified instead is that the file still matches the repo:

• Every path cited in a surviving bullet exists (internal/terminal/cwd.go, internal/store, internal/singleton, frontend/src/lib/git/git-status-store.ts, frontend/src/lib/use-sortable-list.ts, internal/chromium, docs/hooks/).
• Stack claims check out against the manifests: go 1.25.0, React 18, @xterm/xterm ^6, the four providers in internal/providers/providers.go, defaultListenPort = "47821" in main.go.
• The gate commands the file documents actually run: pnpm check exit 0, pnpm test 43 files / 406 tests green.

Noted separately, not fixed here: biome.jsonc:24 still uses recommended, deprecated and removed in the next Biome major — it warns on every pnpm check.