deploy: replace ClickHouse with PostgreSQL/TimescaleDB + OpenSearch in K8s manifests

- Dockerfile: update default SPRING_DATASOURCE_URL to jdbc:postgresql, add OPENSEARCH_URL default env
- deploy/postgres.yaml: new TimescaleDB StatefulSet + headless Service (10Gi PVC, pg_isready probes)
- deploy/opensearch.yaml: new OpenSearch 2.19.0 StatefulSet + headless Service (10Gi PVC, single-node, security disabled)
- deploy/server.yaml: switch datasource env from clickhouse-credentials to postgres-credentials, add OPENSEARCH_URL

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

deploy/opensearch.yaml

@@ -0,0 +1,84 @@
+apiVersion: apps/v1
+kind: StatefulSet
+metadata:
+  name: opensearch
+  namespace: cameleer
+spec:
+  serviceName: opensearch
+  replicas: 1
+  selector:
+    matchLabels:
+      app: opensearch
+  template:
+    metadata:
+      labels:
+        app: opensearch
+    spec:
+      containers:
+        - name: opensearch
+          image: opensearchproject/opensearch:2.19.0
+          ports:
+            - containerPort: 9200
+              name: http
+            - containerPort: 9300
+              name: transport
+          env:
+            - name: discovery.type
+              value: single-node
+            - name: DISABLE_SECURITY_PLUGIN
+              value: "true"
+          volumeMounts:
+            - name: data
+              mountPath: /usr/share/opensearch/data
+          resources:
+            requests:
+              memory: "1Gi"
+              cpu: "200m"
+            limits:
+              memory: "4Gi"
+              cpu: "1000m"
+          livenessProbe:
+            exec:
+              command:
+                - sh
+                - -c
+                - curl -s http://localhost:9200/_cluster/health
+            initialDelaySeconds: 30
+            periodSeconds: 10
+            timeoutSeconds: 5
+            failureThreshold: 3
+          readinessProbe:
+            exec:
+              command:
+                - sh
+                - -c
+                - curl -s http://localhost:9200/_cluster/health
+            initialDelaySeconds: 15
+            periodSeconds: 10
+            timeoutSeconds: 5
+            failureThreshold: 3
+  volumeClaimTemplates:
+    - metadata:
+        name: data
+      spec:
+        accessModes: ["ReadWriteOnce"]
+        resources:
+          requests:
+            storage: 10Gi
+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: opensearch
+  namespace: cameleer
+spec:
+  clusterIP: None
+  selector:
+    app: opensearch
+  ports:
+    - port: 9200
+      targetPort: 9200
+      name: http
+    - port: 9300
+      targetPort: 9300
+      name: transport