Offer follow-up issues from non-blocking review findings

[sebastientaggart]

Adds a post-merge step to /submit-for-review that offers to convert non-blocking review findings (WARNING/NOTE, plus CRITICAL in advisory mode) into follow-up GitHub issues.

Changes

• skills/submit-for-review.md: new Step 9 that gates on review mode, collects non-blocking findings from the review, prompts the user once to select which (if any) to ticket, and creates issues with pool-based labels, no milestone, no assignee. Each issue links back to the merged PR. Added one bullet to the constraints section.
• skills/review-agent.md: one-sentence phrasing rule requiring WARNING/NOTE findings to be self-contained sentences so they can become standalone ticket titles.

Why

Non-blocking findings are often insightful but currently dropped after merge. This makes follow-up an in-flow choice instead of a manual ticket-creation chore.

Issue #49

[sebastientaggart]

Review Summary

Verdict: APPROVE

Findings

• [NOTE] The review-agent phrasing rule only requires WARNING and NOTE findings to be self-contained sentences, but Step 9 in submit-for-review also promotes CRITICAL findings to follow-up issue titles when ai is advisory; consider extending the phrasing rule to CRITICAL so advisory-mode follow-ups inherit the same standalone-title guarantee.
• [NOTE] Step 9 instructs the agent to strip the [WARNING]/[NOTE]/[CRITICAL] prefix for the issue title while keeping the full prefixed text in the body's **Finding:** line, which is a subtle formatting contract that would benefit from an explicit one-line example to prevent drift across adapters.