Add Claude Code review + @claude workflows

Ports the two Claude GitHub workflows from the bang repo (which narya lacked):
claude-code-review.yml auto-reviews PRs; claude.yml responds to @claude
mentions on issues/PRs. Review prompt tuned for narya (wire/streaming compat,
DObject/marshaller correctness, concurrency). Requires the
CLAUDE_CODE_OAUTH_TOKEN repo secret to authenticate.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HhfHCXYp2ctWi76Z91y9Ut

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

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+name: Claude Code Review
+
+on:
+  pull_request:
+    types: [opened, synchronize, ready_for_review, reopened]
+
+jobs:
+  claude-review:
+    runs-on: ubuntu-latest
+    # pull-requests: write is required so `gh pr comment` and the inline-comment
+    # tool can post the review back onto the PR via GITHUB_TOKEN.
+    permissions:
+      contents: read
+      pull-requests: write
+      id-token: write
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 1
+
+      - name: Run Claude Code Review
+        id: claude-review
+        uses: anthropics/claude-code-action@v1
+        with:
+          # Authenticates as the Claude subscription, so review usage is covered
+          # by the plan (no metered API charge). Set the CLAUDE_CODE_OAUTH_TOKEN
+          # secret on this repo (Settings > Secrets and variables > Actions).
+          claude_code_oauth_token: ${{ secrets.CLAUDE_CODE_OAUTH_TOKEN }}
+          prompt: |
+            REPO: ${{ github.repository }}
+            PR NUMBER: ${{ github.event.pull_request.number }}
+
+            Review this pull request. narya is a Java distributed-object /
+            networking library (the Presents framework: DObjects, invocation
+            services/marshallers, the io streaming layer). Focus on:
+            - Correctness bugs and broken edge cases
+            - Wire-protocol / streaming compatibility (field order, Streamable
+              read/writeObject, backwards compatibility of serialized forms)
+            - Thread-safety and concurrency
+            - Security implications
+            - Code quality and existing project conventions
+
+            The PR branch is already checked out in the working directory.
+            Use `gh pr comment` for a short top-level summary.
+            Use `mcp__github_inline_comment__create_inline_comment` (with
+            `confirmed: true`) to flag specific lines.
+            Only post GitHub comments - do not return the review as a message.
+            If you find nothing worth flagging, post a brief "no issues found"
+            summary comment.
+          claude_args: |
+            --allowedTools "mcp__github_inline_comment__create_inline_comment,Bash(gh pr comment:*),Bash(gh pr diff:*),Bash(gh pr view:*)"

.github/workflows/claude.yml

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+name: Claude Code
+
+on:
+  issue_comment:
+    types: [created]
+  pull_request_review_comment:
+    types: [created]
+  issues:
+    types: [opened, assigned]
+  pull_request_review:
+    types: [submitted]
+
+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 == 'issues' && (contains(github.event.issue.body, '@claude') || contains(github.event.issue.title, '@claude')))
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      pull-requests: read
+      issues: read
+      id-token: write
+      actions: read # Required for Claude to read CI results on PRs
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 1
+
+      - name: Run Claude Code
+        id: claude
+        uses: anthropics/claude-code-action@v1
+        with:
+          # Set the CLAUDE_CODE_OAUTH_TOKEN secret on this repo (Settings >
+          # Secrets and variables > Actions) for this to authenticate.
+          claude_code_oauth_token: ${{ secrets.CLAUDE_CODE_OAUTH_TOKEN }}
+
+          # This is an optional setting that allows Claude to read CI results on PRs
+          additional_permissions: |
+            actions: read