Pin GitHub Actions to SHA for security

Update official GitHub Actions (actions/*, github/*) to use pinned
commit SHAs instead of version tags. This satisfies zizmor's
unpinned-action-reference security check.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: oschwald

.github/workflows/clang-addresssanitizer.yml

@@ -17,7 +17,7 @@ jobs:
       CXXFLAGS: -fsanitize=address
       LDFLAGS: -fsanitize=address
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
         with:
           submodules: true
           persist-credentials: false

.github/workflows/clang-analyzer.yml

@@ -10,7 +10,7 @@ jobs:
     name: Clang static analysis
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
         with:
           persist-credentials: false
       - run: sudo apt install clang-tools libipc-run3-perl

.github/workflows/codeql-analysis.yml

@@ -18,7 +18,7 @@ jobs:
 
     steps:
     - name: Checkout repository
-      uses: actions/checkout@v6
+      uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
       with:
         # We must fetch at least the immediate parents so that if this is
         # a pull request then we can checkout the head.
@@ -33,7 +33,7 @@ jobs:
 
     # Initializes the CodeQL tools for scanning.
     - name: Initialize CodeQL
-      uses: github/codeql-action/init@v4
+      uses: github/codeql-action/init@5d4e8d1aca955e8d8589aabd499c5cae939e33c7 # v4.31.9
 
     - run: sudo apt install libipc-run3-perl pandoc
     - run: |
@@ -43,4 +43,4 @@ jobs:
             make safedist
 
     - name: Perform CodeQL Analysis
-      uses: github/codeql-action/analyze@v4
+      uses: github/codeql-action/analyze@5d4e8d1aca955e8d8589aabd499c5cae939e33c7 # v4.31.9

.github/workflows/test.yml

@@ -18,7 +18,7 @@ jobs:
       CC: ${{ matrix.cc }}
       VERBOSE: 1
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
         with:
           submodules: true
           persist-credentials: false
@@ -40,7 +40,7 @@ jobs:
     name: CMake build on ${{matrix.os}}
     runs-on: ${{ matrix.os }}
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
         with:
           submodules: true
           persist-credentials: false

.github/workflows/zizmor.yml

@@ -15,7 +15,7 @@ jobs:
       security-events: write
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v6
+        uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
         with:
           persist-credentials: false