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

templates/components/modals/settings_modal.html

@@ -355,6 +355,23 @@
                         {{ t('settings.updateFlagStrategy.help') }}
                     </div>
                 </div>
+                <div class="setting-item">
+                    <div class="setting-row">
+                        <div class="setting-info">
+                            <label for="hideEarlyAccessUpdates">{{ t('settings.hideEarlyAccessUpdates.label') }}</label>
+                        </div>
+                        <div class="setting-control">
+                            <label class="toggle-switch">
+                                <input type="checkbox" id="hideEarlyAccessUpdates"
+                                       onchange="settingsManager.saveToggleSetting('hideEarlyAccessUpdates', 'hide_early_access_updates')">
+                                <span class="toggle-slider"></span>
+                            </label>
+                        </div>
+                    </div>
+                    <div class="input-help">
+                        {{ t('settings.hideEarlyAccessUpdates.help') }}
+                    </div>
+                </div>
             </div>
 
             <!-- Default Path Customization Section -->