ci: add claude PR review workflow using differential-review skill

Adds a dedicated claude-review.yml workflow that triggers on '@claude review'
comments and runs the differential-review skill from lightninglabs/agent-skills.

Uses the fix commit from anthropics/claude-code-action#963 to handle fork PRs
correctly (refs/pull/N/head instead of fetching by branch name from origin).

Also excludes '@claude review' from the general-purpose claude.yml to prevent
both workflows from firing on the same comment.

Includes a workflow_dispatch trigger for testing before merging.

Author: ziggie1984

.github/workflows/claude-review.yml

@@ -0,0 +1,48 @@
+name: Claude PR Review
+
+on:
+  issue_comment:
+    types: [created]
+  pull_request_review_comment:
+    types: [created]
+  workflow_dispatch:
+    inputs:
+      pr_number:
+        description: 'PR number to review'
+        required: true
+        type: string
+
+jobs:
+  review:
+    if: |
+      github.event.issue.pull_request != null &&
+      (
+        (github.event_name == 'issue_comment' && contains(github.event.comment.body, '@claude review')) ||
+        (github.event_name == 'pull_request_review_comment' && contains(github.event.comment.body, '@claude review'))
+      )
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      pull-requests: write
+      issues: write
+      id-token: write
+      actions: read
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 50
+
+      - name: Fetch agent-skills
+        run: |
+          git clone --depth=1 https://github.com/lightninglabs/agent-skills /tmp/agent-skills
+          cp -r /tmp/agent-skills/skills/differential-review .claude/skills/
+
+      - name: Run Claude Review
+        uses: anthropics/claude-code-action@c9a05208bd8e9f434af6a50011d3fbd091b2d4d2
+        with:
+          claude_code_oauth_token: ${{ secrets.CLAUDE_CODE_OAUTH_TOKEN }}
+          github_token: ${{ secrets.GITHUB_TOKEN }}
+          prompt: "/differential-review"
+          additional_permissions: |
+            actions: read

.github/workflows/claude.yml

@@ -13,9 +13,9 @@ on:
 jobs:
   claude:
     if: |
-      (github.event_name == 'issue_comment' && contains(github.event.comment.body, '@claude')) ||
-      (github.event_name == 'pull_request_review_comment' && contains(github.event.comment.body, '@claude')) ||
-      (github.event_name == 'pull_request_review' && contains(github.event.review.body, '@claude')) ||
+      (github.event_name == 'issue_comment' && contains(github.event.comment.body, '@claude') && !contains(github.event.comment.body, '@claude review')) ||
+      (github.event_name == 'pull_request_review_comment' && contains(github.event.comment.body, '@claude') && !contains(github.event.comment.body, '@claude review')) ||
+      (github.event_name == 'pull_request_review' && contains(github.event.review.body, '@claude') && !contains(github.event.review.body, '@claude review')) ||
       (github.event_name == 'issues' && (contains(github.event.issue.body, '@claude') || contains(github.event.issue.title, '@claude')))
     runs-on: ubuntu-latest
     permissions: