refactor(ci): Rename images to stack-* prefix for clarity

Renamed all Docker images from generic names to stack-* prefix:
- api → stack-api
- web → stack-web
- postgres → stack-postgres
- openbao → stack-openbao
- orchestrator → stack-orchestrator

This prevents confusion with other repositories in the mosaic/
organization on git.mosaicstack.dev.

Registry images:
  git.mosaicstack.dev/mosaic/stack-api
  git.mosaicstack.dev/mosaic/stack-web
  git.mosaicstack.dev/mosaic/stack-postgres
  git.mosaicstack.dev/mosaic/stack-openbao
  git.mosaicstack.dev/mosaic/stack-orchestrator

Local images:
  stack-api:latest
  stack-web:latest
  stack-postgres:latest
  stack-openbao:latest
  stack-orchestrator:latest

Updated files:
- .woodpecker.yml (all build steps + package linking)
- docker-compose.swarm.yml (all image references)
- build-images.sh (local image names)
- deploy-swarm.sh (image validation)

docker-compose.swarm.yml

@@ -3,7 +3,7 @@ services:
   # PostgreSQL Database
   # ======================
   postgres:
-    image: git.mosaicstack.dev/mosaic/postgres:${IMAGE_TAG:-latest}
+    image: git.mosaicstack.dev/mosaic/stack-postgres:${IMAGE_TAG:-latest}
     env_file: .env
     environment:
       POSTGRES_USER: ${POSTGRES_USER:-mosaic}
@@ -56,7 +56,7 @@ services:
   # OpenBao Secrets Vault
   # ======================
   openbao:
-    image: git.mosaicstack.dev/mosaic/openbao:${IMAGE_TAG:-latest}
+    image: git.mosaicstack.dev/mosaic/stack-openbao:${IMAGE_TAG:-latest}
     env_file: .env
     environment:
       OPENBAO_ADDR: ${OPENBAO_ADDR:-http://0.0.0.0:8200}
@@ -225,7 +225,7 @@ services:
   # Mosaic API
   # ======================
   api:
-    image: git.mosaicstack.dev/mosaic/api:${IMAGE_TAG:-latest}
+    image: git.mosaicstack.dev/mosaic/stack-api:${IMAGE_TAG:-latest}
     env_file: .env
     environment:
       NODE_ENV: production
@@ -268,7 +268,7 @@ services:
   # Mosaic Orchestrator
   # ======================
   orchestrator:
-    image: git.mosaicstack.dev/mosaic/orchestrator:${IMAGE_TAG:-latest}
+    image: git.mosaicstack.dev/mosaic/stack-orchestrator:${IMAGE_TAG:-latest}
     env_file: .env
     user: "1000:1000"
     environment:
@@ -309,7 +309,7 @@ services:
   # Mosaic Web
   # ======================
   web:
-    image: git.mosaicstack.dev/mosaic/web:${IMAGE_TAG:-latest}
+    image: git.mosaicstack.dev/mosaic/stack-web:${IMAGE_TAG:-latest}
     env_file: .env
     environment:
       NODE_ENV: production