claude-review: address PR review comments

- Add pull_request_target trigger for fork secret access
- Use pull_request_target in claude-approve if-condition
- Replace CLAUDE.md references with AGENTS.md
- Replace simple approve/comment prompt with comprehensive
  risk-classification prompt (intrinsic PR risk + finding severity)
- Use --request-changes instead of comment when not approving

Author: hieblmi

.github/workflows/claude-code-review.yml

@@ -5,6 +5,8 @@ on:
     types: [created]
   pull_request:
     types: [labeled, synchronize]
+  pull_request_target:
+    types: [labeled, synchronize]
 
 jobs:
   claude-review:
@@ -46,7 +48,7 @@ jobs:
             - Security concerns
             - Test coverage
 
-            Use the repository's CLAUDE.md for guidance on style and conventions. Be constructive and helpful in your feedback.
+            Use the repository's AGENTS.md for guidance on style and conventions. Be constructive and helpful in your feedback.
 
             Use `gh pr comment` with your Bash tool to leave your review as a comment on the PR.
 
@@ -56,7 +58,7 @@ jobs:
 
   claude-approve:
     if: |
-      github.event_name == 'pull_request' &&
+      github.event_name == 'pull_request_target' &&
       contains(github.event.pull_request.labels.*.name, 'low-risk') &&
       (github.event.action == 'labeled' || github.event.action == 'synchronize')
     runs-on: ubuntu-latest
@@ -88,13 +90,40 @@ jobs:
             - Security concerns
             - Test coverage
 
-            Use the repository's CLAUDE.md for guidance on style and conventions.
-
-            If you find NO significant issues, approve the PR using:
-              gh pr review ${{ github.event.pull_request.number }} --approve --body "Your approval message"
-
-            If you find ANY significant issues, do NOT approve. Instead, leave a
-            comment explaining the problems using:
-              gh pr comment ${{ github.event.pull_request.number }} --body "Your review findings"
-
-          claude_args: '--allowed-tools "Bash(gh issue view:*),Bash(gh search:*),Bash(gh issue list:*),Bash(gh pr comment:*),Bash(gh pr diff:*),Bash(gh pr view:*),Bash(gh pr list:*),Bash(gh pr review:*)"'
+            Use the repository's AGENTS.md for guidance on style and conventions.
+
+            Classify the PR's intrinsic risk severity using one of:
+            - critical: must block merge
+            - high: large blast radius or very sensitive code paths
+            - medium: meaningful production or maintainability risk
+            - low: constrained blast radius and straightforward rollback
+
+            Intrinsic risk is about the impact and sensitivity of changed code,
+            even when no concrete bug is found.
+            Any changes touching fund movement, signing/sweeping, swap state
+            transitions, security/authz/authn logic, secrets handling, or DB
+            schema/migrations are at least medium risk.
+
+            Also classify each finding using one of:
+            - critical
+            - high
+            - medium
+            - low
+            - nit
+
+            Decision rule:
+            - Approve ONLY if intrinsic PR risk is low AND highest finding
+              severity is low or nit.
+            - If intrinsic PR risk is medium/high/critical, DO NOT approve and
+              submit a changes-requested review.
+            - If any finding is medium/high/critical, DO NOT approve and submit
+              a changes-requested review.
+            - If uncertain, treat as medium risk.
+
+            If approving:
+              gh pr review ${{ github.event.pull_request.number }} --approve --body "Claude review: intrinsic PR risk low and findings low/nit; safe for low-risk path."
+
+            If NOT approving:
+              gh pr review ${{ github.event.pull_request.number }} --request-changes --body "Claude review: not eligible for low-risk auto-approval. Include intrinsic PR risk and findings with severities."
+
+          claude_args: '--allowed-tools "Bash(gh issue view:*),Bash(gh search:*),Bash(gh issue list:*),Bash(gh pr comment:*),Bash(gh pr diff:*),Bash(gh pr view:*),Bash(gh pr list:*),Bash(gh pr review:*)"'