k8s: simplify workflows deployment to single container

Fix workflow execution failures caused by:
- Port conflict: both containers tried to use :8081
- Incorrect split: /app/worker doesn't have 'server' subcommand
- Multiple health check servers competing for same port

Changes:
- Single container: workflows-worker (activity executor only)
- Removed server/worker split
- No HTTP server (Temporal handles gRPC internally)
- Clean env var setup: TEMPORAL_HOSTPORT, MEMORY_SERVICE_URL, etc.

This allows workflows to execute without port conflicts or crashes.

k8s/workflows-deployment.yaml

@@ -23,61 +23,7 @@ spec:
       imagePullSecrets:
       - name: poimen-registry
       containers:
-      # Workflows server (HTTP, health checks)
-      - name: workflows-server
-        image: forgejo.riotpiao.com/rock/poimen-workflows:latest
-        imagePullPolicy: Always
-        command: ["/app/worker", "server"]
-        ports:
-        - containerPort: 8080
-          name: http
-        env:
-        - name: DATABASE_URL
-          valueFrom:
-            secretKeyRef:
-              name: poimen-db-credentials
-              key: workflows-url
-        - name: TEMPORAL_HOSTPORT
-          valueFrom:
-            configMapKeyRef:
-              name: poimen-config
-              key: temporal-hostport
-        - name: TEMPORAL_NAMESPACE
-          valueFrom:
-            configMapKeyRef:
-              name: poimen-config
-              key: temporal-namespace
-        - name: MEMORY_SERVICE_URL
-          valueFrom:
-            configMapKeyRef:
-              name: poimen-config
-              key: memory-service-url
-        - name: JWT_SECRET
-          valueFrom:
-            secretKeyRef:
-              name: poimen-secrets
-              key: jwt-secret
-        livenessProbe:
-          httpGet:
-            path: /health
-            port: 8080
-          initialDelaySeconds: 10
-          periodSeconds: 10
-        readinessProbe:
-          httpGet:
-            path: /ready
-            port: 8080
-          initialDelaySeconds: 5
-          periodSeconds: 5
-        resources:
-          requests:
-            memory: "256Mi"
-            cpu: "250m"
-          limits:
-            memory: "1Gi"
-            cpu: "1000m"
-
-      # Temporal worker (activity executor)
+      # Temporal activity worker (single role, no HTTP server)
       - name: workflows-worker
         image: forgejo.riotpiao.com/rock/poimen-workflows:latest
         imagePullPolicy: Always