ci: pin third-party actions to commit SHAs (REQ-1.4.10) (#12)

- Pin all uses: refs across codeql.yml, pages.yml, pr-lint.yml, stale.yml
  to immutable commit SHAs with trailing # vX.Y.Z comments
- CodeQL strategy.matrix.language left unchanged at ['actions'] (already correct per S2)
- Permissions and timeout-minutes already present on all jobs; no changes needed

Co-authored-by: Kim Harjamäki <kim.harjamaki@prosimo.fi>

Author: OgeonX-Ai

.github/workflows/codeql.yml

@@ -22,12 +22,12 @@ jobs:
         language: [ 'actions' ]
     steps:
     - name: Checkout repository
-      uses: actions/checkout@v7
+      uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
     - name: Initialize CodeQL
-      uses: github/codeql-action/init@v4
+      uses: github/codeql-action/init@54f647b7e1bb85c95cddabcd46b0c578ec92bc1a # v4.36.3
       with:
         languages: ${{ matrix.language }}
     - name: Autobuild
-      uses: github/codeql-action/autobuild@v4
+      uses: github/codeql-action/autobuild@54f647b7e1bb85c95cddabcd46b0c578ec92bc1a # v4.36.3
     - name: Perform CodeQL Analysis
-      uses: github/codeql-action/analyze@v4
+      uses: github/codeql-action/analyze@54f647b7e1bb85c95cddabcd46b0c578ec92bc1a # v4.36.3

.github/workflows/pages.yml

@@ -16,13 +16,13 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 10
     steps:
-      - uses: actions/checkout@v7
-      - uses: actions/setup-python@v6
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+      - uses: actions/setup-python@ece7cb06caefa5fff74198d8649806c4678c61a1 # v6.3.0
         with:
           python-version: 3.x
       - run: pip install mkdocs-material
       - run: mkdocs build
-      - uses: actions/upload-pages-artifact@v5
+      - uses: actions/upload-pages-artifact@fc324d3547104276b827a68afc52ff2a11cc49c9 # v5.0.0
         with:
           path: ./site
   deploy:
@@ -35,4 +35,4 @@ jobs:
     steps:
       - name: Deploy to GitHub Pages
         id: deployment
-        uses: actions/deploy-pages@v5
+        uses: actions/deploy-pages@cd2ce8fcbc39b97be8ca5fce6e763baed58fa128 # v5.0.0

.github/workflows/pr-lint.yml

@@ -16,6 +16,6 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 10
     steps:
-      - uses: amannn/action-semantic-pull-request@v6
+      - uses: amannn/action-semantic-pull-request@48f256284bd46cdaab1048c3721360e808335d50 # v6.1.1
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

.github/workflows/stale.yml

@@ -13,7 +13,7 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 10
     steps:
-    - uses: actions/stale@v10
+    - uses: actions/stale@eb5cf3af3ac0a1aa4c9c45633dd1ae542a27a899 # v10.3.0
       with:
         stale-issue-message: 'This issue is stale because it has been open 60 days with no activity.'
         stale-pr-message: 'This PR is stale because it has been open 60 days with no activity.'