Fix ~790 basedpyright errors across the test suite:
- Type stub subclasses of real production classes with super().__init__()
- Add missing generic type arguments and Dict[str, Any] annotations
- Add None guards before subscript/member access
- Adapt tests to production API changes (removed dead handlers,
PersistentModelCache.get_default, _i18n_filter_added location)
- Layer 2 fallback: user tags overlapping with auto-tag categories
(HIGH/LOW/I2V/T2V/TI2V/Lightning/Turbo) are merged into auto_tags,
providing manual override when filename-based detection fails.
Matching is case-insensitive so "high"/"High"/"HIGH" all work.
- Refresh on tag edit: save_metadata and add_tags handlers now return
recalculated auto_tags in the response; the frontend passes them to
VirtualScroller.updateSingleItem so badges update immediately without
requiring a page reload.
- 8 new test cases for Layer 2 fallback and case-insensitive matching.
Convert all tags to lowercase in tag processing logic to prevent case sensitivity issues on Windows filesystems. This ensures consistent tag matching and prevents duplicate tags with different cases from being created.
Changes include:
- TagUpdateService now converts tags to lowercase before comparison
- Utils function converts model tags to lowercase before priority resolution
- Test cases updated to reflect lowercase tag expectations
