execute-phase

# Execute Phase Three modes: - **feature phase** (default) — implement one phase of `docs/features/<NN>-<slug>/` using its `TASKS.md`. - **single-pass unit** — a small feature (SPEC `Size: XS/S`; only a `SPEC.md`, no planning artifacts): execute its SPEC's `## Phases` **one phase per invocation**; a SPEC without `## Phases` runs end-to-end in one pass (legacy fallback — see *Workflows*). - **`--fix`** — implement a fix from `docs/fix/<n>-<topic>/`: same phased consumption and legacy fallback. ## Turn contract — every invocation, verify before ending the turn ``` ✓ 1. Branch verified FIRST: `git branch --show-current` was RUN and its output pasted. Output = the default branch → `git switch -c <branch>` was RUN before any edit. NEVER work on main/master. ✓ 2. Phase-lint pre-flight guard RUN against the target phase (after the dependency/own-status gates, before any edit) — its 8 boxes were checked, not assumed. Any FAIL without `--force` → STOP with the fixed block; no edit happens on a non-atomic phase. ✓ 3. The gate was RUN (not assumed): commands + exit codes pasted. ✓ 4. `git add <files>` and `git commit -m "<type>(<scope>): <summary>"` were EXECUTED and the resulting sha is pasted. Describing a commit you did not run counts as NOT committed. ✓ 5. Unit finished (single-pass, --fix, or final phase)? Then `git push` and `gh pr create` were EXECUTED and **the PR URL is printed in the chat** (not every agent shows open PRs — the ...