security: supply chain hardening — CI pinning, dep pinning, and code fixes (#9801)

CI/CD Hardening:
- Pin all 12 GitHub Actions to full commit SHAs (was mutable @vN tags)
- Add explicit permissions: {contents: read} to 4 workflows
- Pin CI pip installs to exact versions (pyyaml==6.0.2, httpx==0.28.1)
- Extend supply-chain-audit.yml to scan workflow, Dockerfile, dependency
  manifest, and Actions version changes

Dependency Pinning:
- Pin git-based Python deps to commit SHAs (atroposlib, tinker, yc-bench)
- Pin WhatsApp Baileys from mutable branch to commit SHA

Tool Registry:
- Reject tool name shadowing from different tool families (plugins/MCP
  cannot overwrite built-in tools). MCP-to-MCP overwrites still allowed.

MCP Security:
- Add tool description content scanning for prompt injection patterns
- Log detailed change diff on dynamic tool refresh at WARNING level

Skill Manager:
- Fix dangerous verdict bug: agent-created skills with dangerous
  findings were silently allowed (ask->None->allow). Now blocked.

.github/workflows/docker-publish.yml

@@ -23,21 +23,21 @@ jobs:
     timeout-minutes: 60
     steps:
       - name: Checkout code
-        uses: actions/checkout@v4
+        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5  # v4
         with:
           submodules: recursive
 
       - name: Set up QEMU
-        uses: docker/setup-qemu-action@v3
+        uses: docker/setup-qemu-action@c7c53464625b32c7a7e944ae62b3e17d2b600130  # v3
 
       - name: Set up Docker Buildx
-        uses: docker/setup-buildx-action@v3
+        uses: docker/setup-buildx-action@8d2750c68a42422c14e847fe6c8ac0403b4cbd6f  # v3
 
       # Build amd64 only so we can `load` the image for smoke testing.
       # `load: true` cannot export a multi-arch manifest to the local daemon.
       # The multi-arch build follows on push to main / release.
       - name: Build image (amd64, smoke test)
-        uses: docker/build-push-action@v6
+        uses: docker/build-push-action@10e90e3645eae34f1e60eeb005ba3a3d33f178e8  # v6
         with:
           context: .
           file: Dockerfile
@@ -56,14 +56,14 @@ jobs:
 
       - name: Log in to Docker Hub
         if: github.event_name == 'push' && github.ref == 'refs/heads/main' || github.event_name == 'release'
-        uses: docker/login-action@v3
+        uses: docker/login-action@c94ce9fb468520275223c153574b00df6fe4bcc9  # v3
         with:
           username: ${{ secrets.DOCKERHUB_USERNAME }}
           password: ${{ secrets.DOCKERHUB_TOKEN }}
 
       - name: Push multi-arch image (main branch)
         if: github.event_name == 'push' && github.ref == 'refs/heads/main'
-        uses: docker/build-push-action@v6
+        uses: docker/build-push-action@10e90e3645eae34f1e60eeb005ba3a3d33f178e8  # v6
         with:
           context: .
           file: Dockerfile
@@ -75,7 +75,7 @@ jobs:
 
       - name: Push multi-arch image (release)
         if: github.event_name == 'release'
-        uses: docker/build-push-action@v6
+        uses: docker/build-push-action@10e90e3645eae34f1e60eeb005ba3a3d33f178e8  # v6
         with:
           context: .
           file: Dockerfile