Embed issue number in branch names for reliable PR-to-issue linking

[sebastientaggart]

Change branch naming convention from feature/<name> to feature/<number>-<name> so that /submit-for-review can deterministically extract the linked issue number from the branch name. This eliminates the unreliable heuristic in Step 3 that caused most PRs to omit issue references, which in turn caused /deploy to leave issues open after release.

Both /start (which creates branches) and /submit-for-review (which reads them) are updated across all four adapters (Claude, Cursor, Codex, Gemini).

Issue #140

[sebastientaggart]

Review Summary

Verdict: APPROVE

Findings

No issues found. Code looks correct and follows project conventions.

The branch naming convention change (feature/<name> to feature/<number>-<name>) is applied consistently across both source templates (skills/start.md, skills/submit-for-review.md) and all four generated adapter files (Claude, Cursor, Codex, Gemini). The sync hashes are updated correctly. The new submit-for-review Step 3 provides a clear extraction rule with a sensible fallback warning for branches created outside /start.