fix: harden v0.7.1 Codex production path

[jayjcc8-cloud]

What changed

• Harden project Hook installation, status, nested Git-root resolution, private permissions, replay output writes, and mutation reporting.
• Validate the complete managed Hook definition and reject tampered, duplicate, or unexpected handlers.
• Anchor generated validation patterns to shell command boundaries while retaining common pytest, unittest, Node, Cargo, Go, and .NET command forms.
• Repair existing SQLite and project-local runtime file permissions and require the generated .gitignore privacy boundary.
• Add a macOS installer smoke job and update v0.7.1 release documentation.

Why

Production Codex validation exposed false-positive Stop blocking from validation names embedded in command arguments. The follow-up audit also found that marker-only health checks could report a disabled handler as healthy and that existing private runtime files or removed ignore rules were not detected.

Impact

Existing generated default anchors are migrated only when they exactly match a prior generated default. User-customized anchors remain unchanged. Re-running install-hooks repairs managed handlers, runtime permissions, and missing ignore entries.

Validation

• uv run ruff format --check .
• uv run ruff check .
• uv run mypy src tests
• uv run pytest — 129 passed
• uv build
• Real Codex 0.147.0 production session and cold-process latency gate completed before this PR