fix(docker): pin the build workflow and keep the image on hash-locked dependencies

Four issues in the new workflow and Dockerfile:

- Every action floated on a mutable major tag, and BuildKit was pinned to
  moby/buildkit:master. This was the only workflow in the repo doing so; the
  other four already pin full commit SHAs. All seven actions are now SHA-pinned
  with a version comment, and the custom driver-opts block is dropped, which
  also removes an unneeded network=host.
- id-token: write was granted with no OIDC consumer anywhere in the workflow —
  no cosign, attestation, provenance, or OIDC login step. Dropped.
- The Dockerfile installed channel extras with 'pip install -e ".[extras]"'
  after the --require-hashes lock install. lark-oapi, qrcode and
  python-telegram-bot are in neither requirements-lock.txt nor its source, so
  the build resolved them and their transitive deps unhashed from PyPI at build
  time — six lines below a comment stating deps come from the hash-pinned lock.
  They now come from requirements-channels-lock.txt (16 pins, all hashed,
  generated under the same constraint as the main lock: 12 packages are shared
  with it and none diverge in version). The project install is --no-deps, which
  is safe because all 44 pyproject base deps are already in the main lock.
- The workflow_dispatch input was interpolated directly into the Summary step's
  run: body. It now passes through env, and the tag is validated against the
  Docker tag grammar before any registry work.

CI verifies the new lock too. The existing 'Verify hash-locked dependencies'
step only dry-ran requirements-lock.txt, so a second lock could have rotted
undetected until a release build failed; both are now dry-run separately, since
the Docker build installs them as two independent --require-hashes passes.

The summary also states that a new GHCR package is private until its visibility
is set once, so the pull command it prints is not read as working out of the box.

.github/workflows/docker-build.yml

@@ -1,5 +1,9 @@
 name: Build and Push Docker Image
 
+# Actions are pinned to immutable commit SHAs, matching every other workflow in
+# this repository. Newer majors exist for the docker/* actions (v4/v6/v7); those
+# are a deliberate, separately testable bump, not a drive-by change here.
+
 on:
   workflow_dispatch:
     inputs:
@@ -20,31 +24,36 @@ jobs:
     permissions:
       contents: read
       packages: write
-      id-token: write
 
     steps:
+      - name: Validate image tag
+        env:
+          IMAGE_TAG: ${{ inputs.image_tag }}
+        run: |
+          # Fail early with a readable message rather than at the registry push.
+          if ! printf '%s' "$IMAGE_TAG" | grep -qE '^[a-zA-Z0-9_][a-zA-Z0-9._-]{0,127}$'; then
+            echo "::error::'$IMAGE_TAG' is not a valid Docker tag." >&2
+            exit 1
+          fi
+
       - name: Checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
 
       - name: Set up Docker Buildx
-        uses: docker/setup-buildx-action@v3
-        with:
-          driver-opts: |
-            image=moby/buildkit:master
-            network=host
+        uses: docker/setup-buildx-action@8d2750c68a42422c14e847fe6c8ac0403b4cbd6f # v3.12.0
 
       - name: Set up QEMU
-        uses: docker/setup-qemu-action@v3
+        uses: docker/setup-qemu-action@c7c53464625b32c7a7e944ae62b3e17d2b600130 # v3.7.0
 
       - name: Log in to GHCR
-        uses: docker/login-action@v3
+        uses: docker/login-action@c94ce9fb468520275223c153574b00df6fe4bcc9 # v3.7.0
         with:
           registry: ${{ env.GHCR_REGISTRY }}
           username: ${{ github.actor }}
           password: ${{ secrets.GITHUB_TOKEN }}
 
       - name: Log in to Docker Hub
-        uses: docker/login-action@v3
+        uses: docker/login-action@c94ce9fb468520275223c153574b00df6fe4bcc9 # v3.7.0
         with:
           registry: ${{ env.DOCKERHUB_REGISTRY }}
           username: ${{ secrets.DOCKERHUB_USERNAME }}
@@ -52,7 +61,7 @@ jobs:
 
       - name: Extract metadata for GHCR
         id: meta-ghcr
-        uses: docker/metadata-action@v5
+        uses: docker/metadata-action@c299e40c65443455700f0fdfc63efafe5b349051 # v5.10.0
         with:
           images: ${{ env.GHCR_REGISTRY }}/${{ env.GHCR_IMAGE_NAME }}
           tags: |
@@ -61,7 +70,7 @@ jobs:
 
       - name: Extract metadata for Docker Hub
         id: meta-dockerhub
-        uses: docker/metadata-action@v5
+        uses: docker/metadata-action@c299e40c65443455700f0fdfc63efafe5b349051 # v5.10.0
         with:
           images: ${{ env.DOCKERHUB_REGISTRY }}/${{ env.DOCKERHUB_IMAGE_NAME }}
           tags: |
@@ -69,7 +78,7 @@ jobs:
             type=raw,value=latest,enable=${{ inputs.image_tag != 'latest' }}
 
       - name: Build and push
-        uses: docker/build-push-action@v5
+        uses: docker/build-push-action@ca052bb54ab0790a636c9b5f226502c73d547a25 # v5.4.0
         with:
           context: .
           file: Dockerfile
@@ -83,7 +92,7 @@ jobs:
           cache-to: type=gha,mode=max
 
       - name: Update Docker Hub description
-        uses: peter-evans/dockerhub-description@v4
+        uses: peter-evans/dockerhub-description@432a30c9e07499fd01da9f8a49f0faf9e0ca5b77 # v4.0.2
         with:
           username: ${{ secrets.DOCKERHUB_USERNAME }}
           password: ${{ secrets.DOCKERHUB_TOKEN }}
@@ -92,15 +101,28 @@ jobs:
           short-description: "AI trading agent with backtesting. Includes Telegram & Feishu channels."
 
       - name: Summary
+        # Inputs go through env, never straight into the script body: a
+        # workflow_dispatch input interpolated into `run:` is a shell-injection
+        # vector even when only maintainers can dispatch it.
+        env:
+          IMAGE_TAG: ${{ inputs.image_tag }}
+          GHCR_IMAGE: ${{ env.GHCR_REGISTRY }}/${{ env.GHCR_IMAGE_NAME }}
+          DOCKERHUB_IMAGE: ${{ env.DOCKERHUB_REGISTRY }}/${{ env.DOCKERHUB_IMAGE_NAME }}
         run: |
-          echo "### Docker Images Built and Pushed" >> $GITHUB_STEP_SUMMARY
-          echo "" >> $GITHUB_STEP_SUMMARY
-          echo "**GHCR:** \`${{ env.GHCR_REGISTRY }}/${{ env.GHCR_IMAGE_NAME }}:${{ inputs.image_tag }}\`" >> $GITHUB_STEP_SUMMARY
-          echo "**Docker Hub:** \`${{ env.DOCKERHUB_REGISTRY }}/${{ env.DOCKERHUB_IMAGE_NAME }}:${{ inputs.image_tag }}\`" >> $GITHUB_STEP_SUMMARY
-          echo "" >> $GITHUB_STEP_SUMMARY
-          echo "**Platforms:** linux/amd64, linux/arm64" >> $GITHUB_STEP_SUMMARY
-          echo "**Channels:** feishu, telegram" >> $GITHUB_STEP_SUMMARY
-          echo "" >> $GITHUB_STEP_SUMMARY
-          echo '```bash' >> $GITHUB_STEP_SUMMARY
-          echo "docker pull ${{ env.GHCR_REGISTRY }}/${{ env.GHCR_IMAGE_NAME }}:${{ inputs.image_tag }}" >> $GITHUB_STEP_SUMMARY
-          echo '```' >> $GITHUB_STEP_SUMMARY
+          {
+            echo "### Docker Images Built and Pushed"
+            echo ""
+            echo "**GHCR:** \`${GHCR_IMAGE}:${IMAGE_TAG}\`"
+            echo "**Docker Hub:** \`${DOCKERHUB_IMAGE}:${IMAGE_TAG}\`"
+            echo ""
+            echo "**Platforms:** linux/amd64, linux/arm64"
+            echo "**Channels:** feishu, telegram (from requirements-channels-lock.txt)"
+            echo ""
+            echo '```bash'
+            echo "docker pull ${GHCR_IMAGE}:${IMAGE_TAG}"
+            echo '```'
+            echo ""
+            echo "> A newly created GHCR package is **private by default**. Until its"
+            echo "> visibility is set to public once in the org package settings, the"
+            echo "> pull above works only for authenticated users with read access."
+          } >> "$GITHUB_STEP_SUMMARY"