feat(ci): add coordinator Docker build/push/link to pipeline

Add Kaniko-based Docker build step for the coordinator service,
push to git.mosaicstack.dev/mosaic/stack-coordinator, and include
it in the link-packages step.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.woodpecker.yml

@@ -266,6 +266,36 @@ steps:
     depends_on:
       - build
 
+  # Build and push Coordinator image using Kaniko
+  docker-build-coordinator:
+    image: gcr.io/kaniko-project/executor:debug
+    environment:
+      GITEA_USER:
+        from_secret: gitea_username
+      GITEA_TOKEN:
+        from_secret: gitea_token
+      CI_COMMIT_BRANCH: ${CI_COMMIT_BRANCH}
+      CI_COMMIT_TAG: ${CI_COMMIT_TAG}
+      CI_COMMIT_SHA: ${CI_COMMIT_SHA}
+    commands:
+      - *kaniko_setup
+      - |
+        DESTINATIONS="--destination git.mosaicstack.dev/mosaic/stack-coordinator:${CI_COMMIT_SHA:0:8}"
+        if [ "$CI_COMMIT_BRANCH" = "main" ]; then
+          DESTINATIONS="$DESTINATIONS --destination git.mosaicstack.dev/mosaic/stack-coordinator:latest"
+        elif [ "$CI_COMMIT_BRANCH" = "develop" ]; then
+          DESTINATIONS="$DESTINATIONS --destination git.mosaicstack.dev/mosaic/stack-coordinator:dev"
+        fi
+        if [ -n "$CI_COMMIT_TAG" ]; then
+          DESTINATIONS="$DESTINATIONS --destination git.mosaicstack.dev/mosaic/stack-coordinator:$CI_COMMIT_TAG"
+        fi
+        /kaniko/executor --context apps/coordinator --dockerfile apps/coordinator/Dockerfile $DESTINATIONS
+    when:
+      - branch: [main, develop]
+        event: [push, manual, tag]
+    depends_on:
+      - build
+
   # ======================
   # Link Packages to Repository
   # ======================
@@ -314,6 +344,7 @@ steps:
         link_package "stack-postgres"
         link_package "stack-openbao"
         link_package "stack-orchestrator"
+        link_package "stack-coordinator"
     when:
       - branch: [main, develop]
         event: [push, manual, tag]
@@ -323,3 +354,4 @@ steps:
       - docker-build-postgres
       - docker-build-openbao
       - docker-build-orchestrator
+      - docker-build-coordinator