feat(tags): add bulk tagging and tag-based filtering

- Add include_tags/exclude_tags query params to /api/events
- Add POST /api/events/bulk-tags endpoint with append/replace modes
- Frontend: add Include tags / Exclude tags filter inputs
- Frontend: add Bulk tag matching button with prompt for tag and mode
- Update filter layout to accommodate new tag fields
- Add tests for tag filtering and bulk tag append/replace

backend/models/api.py

@@ -54,6 +54,11 @@ class TagsUpdateRequest(BaseModel):
     tags: list[str]
 
 
+class BulkTagsRequest(BaseModel):
+    tags: list[str]
+    mode: str = "append"  # "append" or "replace"
+
+
 class CommentAddRequest(BaseModel):
     text: str