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/configs/gateway-config.yaml.tpl

@@ -27,29 +27,22 @@ data:
       model_provider: deepinfra
       model: zai-org/GLM-5
 
-    # License tier model configuration
+    # License tier model configuration (null = fall back to defaults.model)
     license_models:
-      # Free tier models
       free:
-        default: zai-org/GLM-5
-        cost_optimized: zai-org/GLM-5
-        complex: zai-org/GLM-5
-        allowed_models:
-          - zai-org/GLM-5
+        default: ~
+        cost_optimized: ~
+        complex: ~
 
-      # Pro tier models
       pro:
-        default: zai-org/GLM-5
-        cost_optimized: zai-org/GLM-5
-        complex: zai-org/GLM-5
-        blocked_models:
-          - Qwen/Qwen3-235B-A22B-Instruct-2507
+        default: ~
+        cost_optimized: ~
+        complex: ~
 
-      # Enterprise tier models
       enterprise:
-        default: zai-org/GLM-5
-        cost_optimized: zai-org/GLM-5
-        complex: Qwen/Qwen3-235B-A22B-Instruct-2507
+        default: ~
+        cost_optimized: ~
+        complex: ~
 
     # Kubernetes configuration
     kubernetes:
@@ -70,11 +63,6 @@ data:
     redis:
       url: redis://dragonfly:6379
 
-    # Qdrant (for RAG vector search)
-    qdrant:
-      url: http://qdrant:6333
-      collection: gateway_memory
-
     # Iceberg (for durable storage via REST catalog)
     iceberg:
       catalog_uri: http://iceberg-catalog:8181