Add Pipelock agent security scan to CI (#1049)

* Add Pipelock agent security scan to CI

Scans PR diffs for leaked secrets and agent security risks.
Zero config, runs on every PR to main.

* Retrigger CI (v1 action tag now available)

* Harden checkout: persist-credentials false

Pipelock only reads local git history for diff scanning,
no auth token needed in .git/config.

.github/workflows/pipelock.yml

@@ -0,0 +1,24 @@
+name: Pipelock Security Scan
+
+on:
+  pull_request:
+    branches: [main]
+
+permissions:
+  contents: read
+
+jobs:
+  security-scan:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+          persist-credentials: false
+
+      - name: Pipelock Scan
+        uses: luckyPipewrench/pipelock@v1
+        with:
+          scan-diff: 'true'
+          fail-on-findings: 'true'
+          test-vectors: 'false'