Phase 20: Dedicated tag field — chip input, explicit tags array

Tags are now a first-class field rather than being auto-extracted from
the note body. A new TagInput.vue chip component handles tag entry in
both editor views with autocomplete, Enter/comma/backspace UX, and
space-to-hyphen sanitization.

Backend:
- routes/notes.py: create reads tags from JSON; update accepts explicit
  tags (omit = keep existing); append_tag writes to tags array with
  dedup; suggest-tags accepts current_tags filter; remove extract_tags
- routes/tasks.py: same — explicit tags on create/update; remove extract_tags
- services/tag_suggestions.py: current_tags param replaces body extraction
- services/tools.py: create_note tool schema adds tags param; executor passes it
- services/llm.py: system prompt tells LLM to use tags param, not embed #tag in body

Frontend:
- components/TagInput.vue: new chip-based tag input (autocomplete, keyboard UX)
- NoteEditorView.vue / TaskEditorView.vue: tags ref loaded from note.tags;
  TagInput placed between title and body; save/autosave include tags; suggest
  now adds chips; fetchTagSuggestions passes current_tags; dirty tracks tags
- TiptapEditor.vue: remove fetchTags prop and TagSuggestion extension;
  keep TagDecoration for legacy inline #tag highlighting

No DB migration needed — tags column already correct.

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

src/fabledassistant/routes/notes.py

@@ -30,7 +30,6 @@ from fabledassistant.services.notes import (
 )
 from fabledassistant.services.settings import get_setting
 from fabledassistant.services.tag_suggestions import suggest_tags
-from fabledassistant.utils.tags import extract_tags
 
 logger = logging.getLogger(__name__)
 
@@ -67,7 +66,7 @@ async def create_note_route():
     uid = get_current_user_id()
     data = await request.get_json()
     body = data.get("body", "")
-    tags = extract_tags(body)
+    tags = data.get("tags", [])
 
     # Optional task fields
     status = data.get("status")
@@ -111,7 +110,8 @@ async def suggest_tags_route():
     data = await request.get_json()
     title = data.get("title", "")
     body = data.get("body", "")
-    tags = await suggest_tags(uid, title, body)
+    current_tags = data.get("current_tags", [])
+    tags = await suggest_tags(uid, title, body, current_tags=current_tags)
     return jsonify({"suggested_tags": tags})
 
 
@@ -128,10 +128,10 @@ async def append_tag_route(note_id: int):
     if note is None:
         return jsonify({"error": "Note not found"}), 404
 
-    # Append #tag to body
-    new_body = note.body.rstrip() + f"\n#{tag}" if note.body else f"#{tag}"
-    tags = extract_tags(new_body)
-    updated = await update_note(uid, note_id, body=new_body, tags=tags)
+    existing = list(note.tags or [])
+    if tag not in existing:
+        existing.append(tag)
+    updated = await update_note(uid, note_id, tags=existing)
     return jsonify(updated.to_dict())
 
 
@@ -189,8 +189,8 @@ async def update_note_route(note_id: int):
         else:
             fields["due_date"] = None
 
-    if "body" in fields:
-        fields["tags"] = extract_tags(fields["body"])
+    if "tags" in data:
+        fields["tags"] = data["tags"]
     note = await update_note(uid, note_id, **fields)
     if note is None:
         return jsonify({"error": "Note not found"}), 404