feat: add @tag model override support and remove Qdrant dependencies

- Add model-tags parser for @Tag syntax in chat messages
- Support Anthropic models (Sonnet, Haiku, Opus) via @tag
- Remove Qdrant vector database from infrastructure and configs
- Simplify license model config to use null fallbacks
- Add greeting stream after model switch via @tag
- Fix protobuf field names to camelCase for v7 compatibility
- Add 429 rate limit retry logic with exponential backoff
- Remove RAG references from agent harness documentation

deploy/k8s/dev/infrastructure.yaml

@@ -45,68 +45,6 @@ spec:
             memory: "512Mi"
             cpu: "500m"
 ---
-# Qdrant (Vector database for RAG)
-apiVersion: v1
-kind: Service
-metadata:
-  name: qdrant
-spec:
-  selector:
-    app: qdrant
-  ports:
-    - name: http
-      protocol: TCP
-      port: 6333
-      targetPort: 6333
-    - name: grpc
-      protocol: TCP
-      port: 6334
-      targetPort: 6334
-  type: ClusterIP
----
-apiVersion: apps/v1
-kind: StatefulSet
-metadata:
-  name: qdrant
-spec:
-  serviceName: qdrant
-  replicas: 1
-  selector:
-    matchLabels:
-      app: qdrant
-  template:
-    metadata:
-      labels:
-        app: qdrant
-    spec:
-      containers:
-      - name: qdrant
-        image: qdrant/qdrant:latest
-        ports:
-        - containerPort: 6333
-          name: http
-        - containerPort: 6334
-          name: grpc
-        resources:
-          requests:
-            memory: "512Mi"
-            cpu: "200m"
-          limits:
-            memory: "1Gi"
-            cpu: "1000m"
-        volumeMounts:
-        - name: qdrant-data
-          mountPath: /qdrant/storage
-  volumeClaimTemplates:
-  - metadata:
-      name: qdrant-data
-    spec:
-      accessModes: ["ReadWriteOnce"]
-      storageClassName: dev-ephemeral
-      resources:
-        requests:
-          storage: 10Gi
----
 # Kafka (KRaft mode - no Zookeeper needed)
 # Using apache/kafka:3.9.0 instead of confluentinc/cp-kafka because:
 # - cp-kafka's entrypoint script has issues with KRaft configuration