ci: pin all GitHub Actions to commit SHAs

Pin remaining actions that were using mutable tags to specific commit
SHAs for supply chain security. This ensures CI runs are reproducible
and not vulnerable to tag hijacking.

Actions pinned:
- actions/checkout@v6 -> de0fac2e (v6.0.2)
- astral-sh/setup-uv@v7.2.1 -> 803947b9
- anthropics/claude-code-action@v1 -> 2f8ba26a (v1.0.53)

Affected workflows:
- weekly-lockfile-update.yml
- claude.yml
- claude-code-review.yml

Author: maxisbey

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

@@ -19,13 +19,13 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v6
+        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
         with:
           fetch-depth: 1
 
       - name: Run Claude Code Review
         id: claude-review
-        uses: anthropics/claude-code-action@v1
+        uses: anthropics/claude-code-action@2f8ba26a219c06cfb0f468eef8d97055fa814f97 # v1.0.53
         with:
           anthropic_api_key: ${{ secrets.ANTHROPIC_API_KEY }}
           plugin_marketplaces: "https://github.com/anthropics/claude-code.git"

.github/workflows/claude.yml

@@ -27,13 +27,13 @@ jobs:
       actions: read # Required for Claude to read CI results on PRs
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v6
+        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
         with:
           fetch-depth: 1
 
       - name: Run Claude Code
         id: claude
-        uses: anthropics/claude-code-action@v1
+        uses: anthropics/claude-code-action@2f8ba26a219c06cfb0f468eef8d97055fa814f97 # v1.0.53
         with:
           anthropic_api_key: ${{ secrets.ANTHROPIC_API_KEY }}
           use_commit_signing: true

.github/workflows/weekly-lockfile-update.yml

@@ -14,9 +14,9 @@ jobs:
   update-lockfile:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
 
-      - uses: astral-sh/setup-uv@v7.2.1
+      - uses: astral-sh/setup-uv@803947b9bd8e9f986429fa0c5a41c367cd732b41 # v7.2.1
         with:
           version: 0.9.5