ci: migrate to canonical docker-build reusable workflow

Replace bespoke 59-line docker build with the 10-line canonical caller
that uses hanzoai/.github/.github/workflows/docker-build.yml@main.

Native amd64+arm64 ARC runners, semver + branch tags, multi-arch manifest
via the one shared workflow path. Cache-key preserved for scope=kv.

.github/workflows/deploy.yml

@@ -1,58 +1,19 @@
-name: Build and Deploy Hanzo KV
+name: Docker
 
 on:
+  workflow_dispatch:
   push:
     branches: [main, dev, test]
     tags: ['v*']
-    paths:
-      - 'src/**'
-      - 'deps/**'
-      - 'Dockerfile'
-      - '.github/workflows/deploy.yml'
-  workflow_dispatch:
+
+permissions:
+  contents: read
+  packages: write
 
 jobs:
-  build:
-    runs-on: ubuntu-latest
-    permissions:
-      contents: read
-      packages: write
-    steps:
-      - uses: actions/checkout@v4
-
-      - name: Set up QEMU
-        uses: docker/setup-qemu-action@v3
-
-      - name: Set up Docker Buildx
-        uses: docker/setup-buildx-action@v3
-
-      - name: Log in to GHCR
-        uses: docker/login-action@v3
-        with:
-          registry: ghcr.io
-          username: ${{ github.actor }}
-          password: ${{ secrets.GITHUB_TOKEN }}
-
-      - name: Image metadata
-        id: meta
-        uses: docker/metadata-action@v5
-        with:
-          images: ghcr.io/hanzoai/kv
-          tags: |
-            type=raw,value=latest,enable={{is_default_branch}}
-            type=raw,value=9,enable={{is_default_branch}}
-            type=sha,prefix=
-            type=semver,pattern={{version}}
-            type=semver,pattern={{major}}.{{minor}}
-            type=semver,pattern={{major}}
-
-      - name: Build and push
-        uses: docker/build-push-action@v5
-        with:
-          context: .
-          platforms: linux/amd64,linux/arm64
-          push: true
-          tags: ${{ steps.meta.outputs.tags }}
-          labels: ${{ steps.meta.outputs.labels }}
-          cache-from: type=gha,scope=kv
-          cache-to: type=gha,mode=max,scope=kv
+  docker:
+    uses: hanzoai/.github/.github/workflows/docker-build.yml@main
+    with:
+      image: ghcr.io/hanzoai/kv
+      cache-key: kv
+    secrets: inherit