feat: make /review and /ship Greptile-aware

/review: Step 2.5 fetches and classifies Greptile comments, Step 5
resolves them with AskUserQuestion for valid issues and false positives.

/ship: Step 3.75 triages Greptile comments between pre-landing review
and version bump. Adds Greptile Review section to PR body in Step 8.
Re-runs tests if any Greptile fixes are applied.

review/SKILL.md

@@ -36,6 +36,16 @@ Read `.claude/skills/review/checklist.md`.
 
 ---
 
+## Step 2.5: Check for Greptile review comments
+
+Read `.claude/skills/review/greptile-triage.md` and follow the fetch, filter, and classify steps.
+
+**If no PR exists, `gh` fails, API returns an error, or there are zero Greptile comments:** Skip this step silently. Greptile integration is additive — the review works without it.
+
+**If Greptile comments are found:** Store the classifications (VALID & ACTIONABLE, VALID BUT ALREADY FIXED, FALSE POSITIVE, SUPPRESSED) — you will need them in Step 5.
+
+---
+
 ## Step 3: Get the diff
 
 Fetch the latest main to avoid false positives from a stale local main:
@@ -68,6 +78,30 @@ Follow the output format specified in the checklist. Respect the suppressions
 - If only non-critical issues found: output findings. No further action needed.
 - If no issues found: output `Pre-Landing Review: No issues found.`
 
+### Greptile comment resolution
+
+After outputting your own findings, if Greptile comments were classified in Step 2.5:
+
+**Include a Greptile summary in your output header:** `+ N Greptile comments (X valid, Y fixed, Z FP)`
+
+1. **VALID & ACTIONABLE comments:** These are already included in your CRITICAL findings — they follow the same AskUserQuestion flow (A: Fix it now, B: Acknowledge, C: False positive). If the user chooses C (false positive), post a reply using the appropriate API from the triage doc and save the pattern to `~/.gstack/greptile-history.md` (type: fp).
+
+2. **FALSE POSITIVE comments:** Present each one via AskUserQuestion:
+   - Show the Greptile comment: file:line (or [top-level]) + body summary + permalink URL
+   - Explain concisely why it's a false positive
+   - Options:
+     - A) Reply to Greptile explaining why this is incorrect (recommended if clearly wrong)
+     - B) Fix it anyway (if low-effort and harmless)
+     - C) Ignore — don't reply, don't fix
+
+   If the user chooses A, post a reply using the appropriate API from the triage doc and save the pattern to `~/.gstack/greptile-history.md` (type: fp).
+
+3. **VALID BUT ALREADY FIXED comments:** Reply acknowledging the catch — no AskUserQuestion needed:
+   - Post reply: `"Good catch — already fixed in <commit-sha>."`
+   - Save to `~/.gstack/greptile-history.md` (type: already-fixed)
+
+4. **SUPPRESSED comments:** Skip silently — these are known false positives from previous triage.
+
 ---
 
 ## Important Rules

ship/SKILL.md

@@ -23,6 +23,7 @@ You are running the `/ship` workflow. This is a **non-interactive, fully automat
 - Test failures (stop, show failures)
 - Pre-landing review finds CRITICAL issues and user chooses to fix (not acknowledge or skip)
 - MINOR or MAJOR version bump needed (ask — see Step 4)
+- Greptile review comments that need user decision (complex fixes, false positives)
 
 **Never stop for:**
 - Uncommitted changes (always include them)
@@ -171,6 +172,43 @@ Save the review output — it goes into the PR body in Step 8.
 
 ---
 
+## Step 3.75: Address Greptile review comments (if PR exists)
+
+Read `.claude/skills/review/greptile-triage.md` and follow the fetch, filter, and classify steps.
+
+**If no PR exists, `gh` fails, API returns an error, or there are zero Greptile comments:** Skip this step silently. Continue to Step 4.
+
+**If Greptile comments are found:**
+
+Include a Greptile summary in your output: `+ N Greptile comments (X valid, Y fixed, Z FP)`
+
+For each classified comment:
+
+**VALID & ACTIONABLE:** Use AskUserQuestion with:
+- The comment (file:line or [top-level] + body summary + permalink URL)
+- Your recommended fix
+- Options: A) Fix now (recommended), B) Acknowledge and ship anyway, C) It's a false positive
+- If user chooses A: apply the fix, commit the fixed files (`git add <fixed-files> && git commit -m "fix: address Greptile review — <brief description>"`), reply to the comment (`"Fixed in <commit-sha>."`), and save to `~/.gstack/greptile-history.md` (type: fix).
+- If user chooses C: reply explaining the false positive, save to history (type: fp).
+
+**VALID BUT ALREADY FIXED:** Reply acknowledging the catch — no AskUserQuestion needed:
+- Post reply: `"Good catch — already fixed in <commit-sha>."`
+- Save to `~/.gstack/greptile-history.md` (type: already-fixed)
+
+**FALSE POSITIVE:** Use AskUserQuestion:
+- Show the comment and why you think it's wrong (file:line or [top-level] + body summary + permalink URL)
+- Options:
+  - A) Reply to Greptile explaining the false positive (recommended if clearly wrong)
+  - B) Fix it anyway (if trivial)
+  - C) Ignore silently
+- If user chooses A: post reply using the appropriate API from the triage doc, save to history (type: fp)
+
+**SUPPRESSED:** Skip silently — these are known false positives from previous triage.
+
+**After all comments are resolved:** If any fixes were applied, the tests from Step 3 are now stale. **Re-run tests** (Step 3) before continuing to Step 4. If no fixes were applied, continue to Step 4.
+
+---
+
 ## Step 4: Version bump (auto-decide)
 
 1. Read the current `VERSION` file (4-digit format: `MAJOR.MINOR.PATCH.MICRO`)
@@ -275,6 +313,11 @@ gh pr create --title "<type>: <summary>" --body "$(cat <<'EOF'
 ## Eval Results
 <If evals ran: suite names, pass/fail counts, cost dashboard summary. If skipped: "No prompt-related files changed — evals skipped.">
 
+## Greptile Review
+<If Greptile comments were found: bullet list with [FIXED] / [FALSE POSITIVE] / [ALREADY FIXED] tag + one-line summary per comment>
+<If no Greptile comments found: "No Greptile comments.">
+<If no PR existed during Step 3.75: omit this section entirely>
+
 ## Test plan
 - [x] All Rails tests pass (N runs, 0 failures)
 - [x] All Vitest tests pass (N tests)