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/notes.py

@@ -197,6 +197,7 @@ async def update_note(user_id: int, note_id: int, **fields: object) -> Note | No
         # Snapshot before changes for version creation
         old_body = note.body
         old_title = note.title
+        old_tags = list(note.tags or [])
         for key, value in fields.items():
             if not hasattr(note, key):
                 continue
@@ -214,7 +215,7 @@ async def update_note(user_id: int, note_id: int, **fields: object) -> Note | No
     # Create a version snapshot when body actually changes
     if "body" in fields and fields["body"] != old_body:
         from fabledassistant.services.note_versions import create_version
-        await create_version(user_id, note_id, old_body, old_title)
+        await create_version(user_id, note_id, old_body, old_title, old_tags)
 
     return note
 
@@ -234,19 +235,24 @@ async def delete_note(user_id: int, note_id: int) -> bool:
 
 async def get_all_tags(user_id: int, q: str | None = None) -> list[str]:
     async with async_session() as session:
-        result = await session.execute(
-            text(
-                "SELECT DISTINCT unnest(tags) AS tag FROM notes"
-                " WHERE tags != '{}' AND user_id = :user_id"
-            ).bindparams(user_id=user_id)
-        )
-        all_tags = [row[0] for row in result.fetchall()]
-
         if q:
-            q_lower = q.lower()
-            all_tags = [t for t in all_tags if q_lower in t.lower()]
-
-        return sorted(all_tags)
+            result = await session.execute(
+                text(
+                    "SELECT DISTINCT tag FROM"
+                    " (SELECT unnest(tags) AS tag FROM notes"
+                    "  WHERE tags != '{}' AND user_id = :user_id) t"
+                    " WHERE tag ILIKE :q_pattern ORDER BY tag LIMIT 100"
+                ).bindparams(user_id=user_id, q_pattern=f"%{q}%")
+            )
+        else:
+            result = await session.execute(
+                text(
+                    "SELECT DISTINCT unnest(tags) AS tag FROM notes"
+                    " WHERE tags != '{}' AND user_id = :user_id"
+                    " ORDER BY tag LIMIT 100"
+                ).bindparams(user_id=user_id)
+            )
+        return [row[0] for row in result.fetchall()]
 
 
 async def convert_note_to_task(user_id: int, note_id: int) -> Note:
@@ -291,6 +297,7 @@ async def search_notes_for_context(
     keywords: list[str],
     exclude_ids: set[int] | None = None,
     limit: int = 3,
+    project_id: int | None = None,
 ) -> list[Note]:
     """Search notes by keywords with OR logic. Optimized for context building — no count query."""
     async with async_session() as session:
@@ -301,6 +308,8 @@ async def search_notes_for_context(
             keyword_filters.append(or_(Note.title.ilike(pattern), Note.body.ilike(pattern)))
 
         query = select(Note).where(Note.user_id == user_id, or_(*keyword_filters))
+        if project_id is not None:
+            query = query.where(Note.project_id == project_id)
         if exclude_ids:
             query = query.where(Note.id.notin_(exclude_ids))
         query = query.order_by(Note.updated_at.desc()).limit(limit)