IS_CHANGED only receives constant inputs, so a linked text always
arrived as None and the node kept serving its cached first expansion.
Declare hidden PROMPT/UNIQUE_ID inputs and walk the prompt graph to
the upstream node: rerun only when its constants contain dynamic
syntax or cannot be statically resolved, keep caching for static
linked text.
Fixes#1120
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)