feat: write gate and command gate in report-only mode #327

Why

The rule needs enforcement (design: Making it stick).

In scope

file-write.mjs reports writes outside the project root, the cache and the Codex register as OutOfScopeWrite; the exec wrapper reports npm install -g, claude mcp add -s user, codex mcp add and launchctl; add the lint rule in warn mode.

Out of scope

Throwing (#378).

Acceptance criteria

• Every out-of-scope write and command is reported in tests
• The lint rule flags direct fs writes in writer modules

Dependencies

Blocked by: #320

Blocks: #328, #385

Plan

• Release: 4.0.0-beta.1
• Size: size:M · Workstream: ws:project-scope
• Epic: feat: project-scope P0, removals and the enforcement baseline (epic) #295
• Card: P0-07 in the card inventory
• Sources: Design (docs(plans): project-scoped management design and its prerequisites #289) Making it stick

Verification

• pnpm test
• pnpm run lint