feat: migrate realtime-collab from Docker Compose to k3s

Add k3s manifests for postgres, redis, and backend

Fix users table constraint and init.sql

k3s/postgres.yaml

@@ -0,0 +1,69 @@
+apiVersion: v1
+kind: PersistentVolumeClaim
+metadata:
+  name: postgres-pvc
+spec:
+  accessModes:
+    - ReadWriteOnce
+  resources:
+    requests:
+      storage: 5Gi
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: postgres
+spec:
+  replicas: 1
+  selector:
+    matchLabels:
+      app: postgres
+  template:
+    metadata:
+      labels:
+        app: postgres
+    spec:
+      containers:
+        - name: postgres
+          image: postgres:16-alpine
+          args: ["-c", "shared_buffers=128MB", "-c", "max_connections=50"]
+          ports:
+            - containerPort: 5432
+          envFrom:
+            - secretRef:
+                name: realtime-collab-secret
+          resources:
+            requests:
+              memory: "64Mi"
+              cpu: "100m"
+            limits:
+              memory: "256Mi"
+              cpu: "500m"
+          volumeMounts:
+            - name: postgres-data
+              mountPath: /var/lib/postgresql/data
+            - name: init-sql
+              mountPath: /docker-entrypoint-initdb.d
+          readinessProbe:
+            exec:
+              command: ["pg_isready", "-U", "$(POSTGRES_USER)", "-d", "$(POSTGRES_DB)"]
+            initialDelaySeconds: 10
+            periodSeconds: 10
+      volumes:
+        - name: postgres-data
+          persistentVolumeClaim:
+            claimName: postgres-pvc
+        - name: init-sql
+          configMap:
+            name: postgres-init-sql
+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: postgres
+spec:
+  selector:
+    app: postgres
+  ports:
+    - port: 5432
+      targetPort: 5432