feat(early-access): implement EA filtering and UI improvements

Add Early Access version support with filtering and improved UI:

Backend:
- Add is_early_access and early_access_ends_at fields to ModelVersionRecord
- Implement two-phase EA detection (bulk API + single API enrichment)
- Add hide_early_access_updates setting to filter EA updates
- Update has_update() and has_updates_bulk() to respect EA filter setting
- Add _enrich_early_access_details() for precise EA time fetching
- Fix setting propagation through base_model_service and model_update_service

Frontend:
- Add smart relative time display for EA (in Xh, in Xd, or date)
- Replace EA label with clock icon in metadata (fa-clock)
- Show Download button with bolt icon for EA versions (fa-bolt)
- Change EA badge color to #F59F00 (CivitAI Buzz theme)
- Fix toggle UI for hide_early_access_updates setting
- Add translation keys for EA time formatting

Tests:
- Update all tests to pass with new EA functionality
- Add test coverage for EA filtering logic

Closes #815

tests/routes/test_model_update_handler.py

@@ -66,6 +66,7 @@ async def test_build_version_context_includes_static_urls():
         service=service,
         update_service=SimpleNamespace(),
         metadata_provider_selector=lambda *_: None,
+        settings_service=SimpleNamespace(get=lambda *_: False),
         logger=logging.getLogger(__name__),
     )
 
@@ -145,6 +146,7 @@ async def test_refresh_model_updates_filters_records_without_updates():
         service=service,
         update_service=update_service,
         metadata_provider_selector=metadata_selector,
+        settings_service=SimpleNamespace(get=lambda *_: False),
         logger=logging.getLogger(__name__),
     )
 
@@ -207,6 +209,7 @@ async def test_refresh_model_updates_with_target_ids():
         service=service,
         update_service=update_service,
         metadata_provider_selector=metadata_selector,
+        settings_service=SimpleNamespace(get=lambda *_: False),
         logger=logging.getLogger(__name__),
     )
 
@@ -258,6 +261,7 @@ async def test_refresh_model_updates_accepts_snake_case_ids():
         service=service,
         update_service=update_service,
         metadata_provider_selector=metadata_selector,
+        settings_service=SimpleNamespace(get=lambda *_: False),
         logger=logging.getLogger(__name__),
     )
 
@@ -337,6 +341,7 @@ async def test_fetch_missing_license_data_updates_metadata(monkeypatch):
         service=DummyService(cache),
         update_service=SimpleNamespace(),
         metadata_provider_selector=metadata_selector,
+        settings_service=SimpleNamespace(get=lambda *_: False),
         logger=logging.getLogger(__name__),
     )
 
@@ -423,6 +428,7 @@ async def test_fetch_missing_license_data_filters_model_ids(monkeypatch):
         service=DummyService(cache),
         update_service=SimpleNamespace(),
         metadata_provider_selector=metadata_selector,
+        settings_service=SimpleNamespace(get=lambda *_: False),
         logger=logging.getLogger(__name__),
     )