feat: add smart page creation endpoint with HybridRAG research

Add POST /wiki/pages/smart-create endpoint that combines research with
content generation for the librarian agent:

- Run HybridRAG search on topic (wiki + graph + web)
- Use LLM (WikiPageWriter) to synthesize findings into wiki content
- Create page with proper attribution and sources
- Schedule background tasks for vector/graph indexing
- Apply bidirectional entity linking (forward + backward links)

New files:
- src/services/entity_linking_utils.py - shared entity linking helper

Modified:
- src/models/wiki.py - WikiSmartCreateRequest/Response models
- src/services/wiki_service.py - smart_create_page() method
- src/routers/wiki.py - /pages/smart-create endpoint

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/models/wiki.py

@@ -8,7 +8,7 @@ Models for:
 """
 
 from pydantic import BaseModel, Field, field_validator
-from typing import Optional, List
+from typing import Optional, List, Dict, Any
 from datetime import datetime
 
 
@@ -190,3 +190,44 @@ class DossierOperationResponse(BaseModel):
     dossier_name: str = Field(..., description="Dossier name")
     index_page_id: Optional[int] = Field(None, description="Index page ID (if created)")
     index_page_path: Optional[str] = Field(None, description="Index page path (if created)")
+
+
+# Smart create models (HybridRAG-powered page creation)
+class WikiSmartCreateRequest(BaseModel):
+    """Request model for smart page creation with research."""
+    topic: str = Field(..., min_length=1, max_length=500, description="Topic to research and create page about")
+    path: Optional[str] = Field(None, description="Page path (auto-generated from topic if not provided)")
+    tags: List[str] = Field(default_factory=list, description="Tags for the page")
+    user: Optional[str] = Field(None, description="User identifier")
+    include_web_research: bool = Field(default=True, description="Include web search results")
+    include_wiki_search: bool = Field(default=True, description="Include existing wiki knowledge")
+
+    @field_validator("tags")
+    @classmethod
+    def validate_tags(cls, v: List[str]) -> List[str]:
+        """Validate and clean tags."""
+        cleaned = [tag.strip() for tag in v if tag.strip()]
+        return list(set(cleaned))
+
+    @field_validator("path")
+    @classmethod
+    def validate_path(cls, v: Optional[str]) -> Optional[str]:
+        """Validate page path if provided."""
+        if v is None:
+            return None
+        # Ensure path starts with /
+        if not v.startswith("/"):
+            v = f"/{v}"
+        # Remove trailing slash
+        if v.endswith("/") and v != "/":
+            v = v.rstrip("/")
+        return v
+
+
+class WikiSmartCreateResponse(BaseModel):
+    """Response model for smart page creation."""
+    page: WikiPage = Field(..., description="Created wiki page")
+    research_summary: Dict[str, Any] = Field(..., description="Summary of research used")
+    sources_used: int = Field(..., description="Number of sources incorporated")
+    search_id: Optional[str] = Field(None, description="HybridRAG search ID for reference")
+    entity_linking: Dict[str, int] = Field(default_factory=dict, description="Entity linking statistics")