- Updated `NostrClient.fetchListIncrementally` to accept a `since` override.
- Updated `HashtagPreferencesService.load` to pass `since` based on local cache timestamp.
- Ensures preferences are refreshed if local state is stale or missing, overriding potentially incorrect `SyncMetadataStore` state.
- Added regression tests for `fetchListIncrementally` since parameter logic.
Co-authored-by: PR0M3TH3AN <[email protected]>