feat(library-desk): add configuration for HybridRAG and enhance multi-tenancy

Configuration:
- Add HybridRAG settings (reranker model, search limits)
- Change Wiki.js auth from API key to username/password
- Configure vector, graph, and web search limits

Multi-tenancy:
- Add get_neo4j_user_base_label() for entity node labeling
- Support title-cased labels following Neo4j conventions
- Maintain namespace isolation for entities vs documents

services/library-desk/src/config.py

@@ -32,7 +32,8 @@ class Settings(BaseSettings):
 
     # Wiki.js Configuration
     wikijs_url: str = Field(default="http://wiki:3000", description="Wiki.js URL")
-    wikijs_api_key: str = Field(..., description="Wiki.js API key")
+    wikijs_username: str = Field(..., description="Wiki.js username")
+    wikijs_password: str = Field(..., description="Wiki.js password")
 
     # SearXNG Configuration
     searxng_url: str = Field(default="http://searxng:8080", description="SearXNG URL")
@@ -41,6 +42,13 @@ class Settings(BaseSettings):
     ollama_url: str = Field(default="http://ollama:11434", description="Ollama URL")
     ollama_model: str = Field(default="nomic-embed-text", description="Ollama embedding model")
 
+    # HybridRAG Configuration
+    reranker_model: str = Field(default="mistral-nemo", description="Model for LLM re-ranking")
+    reranker_enabled: bool = Field(default=True, description="Enable LLM re-ranking")
+    hybrid_rag_vector_limit: int = Field(default=10, ge=1, le=50, description="Vector search limit")
+    hybrid_rag_graph_limit: int = Field(default=10, ge=1, le=50, description="Graph search limit")
+    hybrid_rag_web_limit: int = Field(default=5, ge=1, le=20, description="Web search limit")
+
     # Redis Configuration (for job tracking - separate DB from wiki)
     redis_host: str = Field(default="redis-shared", description="Redis host")
     redis_port: int = Field(default=6379, description="Redis port")