chore(ci): pin the supply chain and surface build provenance

Every workflow action is pinned to a commit SHA, dependabot auto-merge
is limited to patch and minor updates behind the now-required status
checks on main, and the audit, Trivy and ESLint gates block instead of
warning. The published image finally carries its build SHA and build
timestamp so the version endpoint can prove which commit is running.
The API-token HMAC key fails closed under 32 characters, compose pins
the database minor and denies privilege escalation, and the changelog
drops working-note references in favour of neutral wording.

.github/workflows/integration.yml

@@ -6,16 +6,19 @@ on:
   push:
     branches: [main]
 
+permissions:
+  contents: read
+
 jobs:
   integration:
     runs-on: ubuntu-latest
     timeout-minutes: 15
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6.0.3
 
-      - uses: pnpm/action-setup@v6
+      - uses: pnpm/action-setup@0e279bb959325dab635dd2c09392533439d90093 # v6.0.8
 
-      - uses: actions/setup-node@v6
+      - uses: actions/setup-node@48b55a011bda9f5d6aeb4c2d9c7362e8dae4041e # v6.4.0
         with:
           node-version: 22
           cache: pnpm