fix: all tests

- Updated `searchNotes.ts` to retrieve the default embedding model using `getSearchEmbedModel()` instead of directly accessing `defaultEmbedModel`.
- Enhanced `SearchModal.ts` to ensure tag suggestions are prefixed with '#' if not already.
- Introduced `spaceFilePickerState.ts` to manage selected space files and related utility functions.
- Simplified `aiTransport.ts` by removing the unused `electronNetFetchPromise` and streamlining the fetch resolution logic.
- Deprecated `buildFilterFromGroups` and `buildFilterFromDrillStack` in `views.ts`, replacing them with `buildFilterFromSegments`.
- Added `openaiProvider` import in `index.ts` and updated `getProviderDefinition` to include it in the provider lookup.
- Implemented recent note tracking in `recentNotes.ts` to include both recently opened and created notes.
- Cleaned up `chatStore.svelte.ts` by removing unnecessary re-exports for backward compatibility.
- Removed `defaultEmbedModel` from `dataStore.svelte.ts` and adjusted related logic to use embedding indexes.
- Updated tests in `AgentManager.test.ts` and `searchNotes.test.ts` to reflect changes in provider handling and embedding model retrieval.
- Refined `pendingChangesStore.test.ts` to align with new privacy handling logic in the data store.