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

- Pin all uses: refs across codeql.yml and pages.yml to immutable commit SHAs
  with trailing # vX.Y.Z comments
- ci.yml confirmed already fully SHA-pinned (2026-07-06 audit) - left untouched
- 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

@@ -19,12 +19,12 @@ jobs:
         language: [ 'python' ]
     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

@@ -14,13 +14,13 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 15
     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:
@@ -36,4 +36,4 @@ jobs:
     steps:
       - name: Deploy to GitHub Pages
         id: deployment
-        uses: actions/deploy-pages@v5
+        uses: actions/deploy-pages@cd2ce8fcbc39b97be8ca5fce6e763baed58fa128 # v5.0.0