Project-aware assist, link suggestions, project-scoped RAG, semantic search tool, SSE race fix

- Writing assistant: inject project notes as context (definition-tagged first), wikilink suggestions
- Link suggestions: server-side endpoint finds unlinked term occurrences, NoteEditorView sidebar panel
- Project-scoped RAG: ChatView ProjectSelector filters semantic+keyword search to selected project
- Semantic search tool: LLM search_notes upgraded to hybrid semantic (0.40 threshold) + keyword merge
- SSE race condition fix: drain remaining events after stream loop exits in chat.py and notes.py
- RAG_AUTO_SNIPPET raised 800→4000; sidebar include uses full note body; MAX_BODY_CHARS 8000→24000
- Enter-to-submit on writing assistant instruction textareas (note and task editors)
- DiffView: equal-line collapsing with 3-line context around changes

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

src/fabledassistant/services/note_versions.py

@@ -6,9 +6,11 @@ from fabledassistant.models.note_version import NoteVersion
 MAX_VERSIONS = 20
 
 
-async def create_version(user_id: int, note_id: int, body: str, title: str) -> NoteVersion:
+async def create_version(
+    user_id: int, note_id: int, body: str, title: str, tags: list[str] | None = None
+) -> NoteVersion:
     async with async_session() as session:
-        version = NoteVersion(note_id=note_id, user_id=user_id, body=body, title=title)
+        version = NoteVersion(note_id=note_id, user_id=user_id, body=body, title=title, tags=tags or [])
         session.add(version)
         await session.commit()
         await session.refresh(version)