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

static/js/managers/SettingsManager.js

@@ -475,6 +475,12 @@ export class SettingsManager {
             updateFlagStrategySelect.value = state.global.settings.update_flag_strategy || 'same_base';
         }
 
+        // Set hide early access updates setting
+        const hideEarlyAccessUpdatesCheckbox = document.getElementById('hideEarlyAccessUpdates');
+        if (hideEarlyAccessUpdatesCheckbox) {
+            hideEarlyAccessUpdatesCheckbox.checked = state.global.settings.hide_early_access_updates || false;
+        }
+
         // Set optimize example images setting
         const optimizeExampleImagesCheckbox = document.getElementById('optimizeExampleImages');
         if (optimizeExampleImagesCheckbox) {