feat(frontend): opt-in Other Models toggles, hidden nav and announcement

- The Other nav entry is hidden while the feature is off
  (nav-item--hidden, toggled client-side after enabling) and now uses the
  fa-shapes icon.
- Shared utils/otherModels.js helpers (enable through the settings API,
  open the settings Library section) are reused by the disabled page, the
  announcement banner and the download modal.
- BannerService registers a one-time dismissible "other-models-announcement"
  banner while the feature is off; SettingsManager drops the banner and
  updates the nav when the master switch flips.
- A disabled download routing answer now surfaces a showActionToast with an
  "Enable Other Models" action.
- Settings UI: master toggle + five sub_type checkboxes whose default-root
  selects are disabled when unchecked; i18n keys added to en.json and synced
  (other locales keep TODO placeholders).

static/js/managers/BannerService.js

@@ -6,9 +6,11 @@ import {
 import { translate } from '../utils/i18nHelpers.js';
 import { state } from '../state/index.js';
 import { getModelApiClient } from '../api/modelApiFactory.js';
+import { enableOtherModels, openOtherModelsSettings } from '../utils/otherModels.js';
 
 const COMMUNITY_SUPPORT_BANNER_ID = 'community-support';
 const CACHE_HEALTH_BANNER_ID = 'cache-health-warning';
+const OTHER_MODELS_BANNER_ID = 'other-models-announcement';
 const COMMUNITY_SUPPORT_BANNER_DELAY_MS = 5 * 24 * 60 * 60 * 1000; // 5 days
 const COMMUNITY_SUPPORT_FIRST_SEEN_AT_KEY = 'community_support_banner_first_seen_at';
 const COMMUNITY_SUPPORT_VERSION_KEY = 'community_support_banner_state_version';
@@ -80,6 +82,7 @@ class BannerService {
         });
 
         this.prepareCommunitySupportBanner();
+        this.prepareOtherModelsBanner();
 
         await this.showActiveBanners();
         this.initialized = true;
@@ -541,6 +544,92 @@ class BannerService {
         this.updateContainerVisibility();
     }
 
+    /**
+     * Announce the opt-in Other Models management to users who have not turned
+     * it on yet. Dismissal is persisted through the shared dismissed_banners
+     * setting, so users who are not interested are not nagged again.
+     */
+    prepareOtherModelsBanner() {
+        if (state.global.settings.enable_other_models) {
+            return;
+        }
+        if (this.isBannerDismissed(OTHER_MODELS_BANNER_ID)) {
+            return;
+        }
+
+        this.registerBanner(OTHER_MODELS_BANNER_ID, {
+            id: OTHER_MODELS_BANNER_ID,
+            title: translate(
+                'banners.otherModels.title',
+                {},
+                'Other Models Management is available'
+            ),
+            content: translate(
+                'banners.otherModels.content',
+                {},
+                'Scan and manage VAE, upscaler, text encoder and CLIP vision files — and download them from CivitAI — from one dedicated page.'
+            ),
+            actions: [
+                {
+                    text: translate(
+                        'banners.otherModels.enable',
+                        {},
+                        'Enable Other Models'
+                    ),
+                    icon: 'fas fa-shapes',
+                    type: 'primary',
+                    action: 'enable-other-models'
+                },
+                {
+                    text: translate(
+                        'banners.otherModels.openSettings',
+                        {},
+                        'Open Settings'
+                    ),
+                    icon: 'fas fa-cog',
+                    type: 'secondary',
+                    action: 'open-other-models-settings'
+                }
+            ],
+            dismissible: true,
+            priority: 0,
+            onRegister: (bannerElement) => {
+                const enableButton = bannerElement.querySelector(
+                    '.banner-action[data-action="enable-other-models"]'
+                );
+                if (enableButton) {
+                    enableButton.addEventListener('click', (event) => {
+                        event.preventDefault();
+                        enableOtherModels().catch((error) => {
+                            console.error('Failed to enable Other Models:', error);
+                        });
+                    });
+                }
+
+                const settingsButton = bannerElement.querySelector(
+                    '.banner-action[data-action="open-other-models-settings"]'
+                );
+                if (settingsButton) {
+                    settingsButton.addEventListener('click', (event) => {
+                        event.preventDefault();
+                        openOtherModelsSettings();
+                    });
+                }
+            }
+        });
+
+        this.updateContainerVisibility();
+    }
+
+    /**
+     * Drop the Other Models announcement once the feature is enabled.
+     * Dismissal is deliberately NOT persisted, so the announcement can come
+     * back if the user switches the feature off again.
+     */
+    removeOtherModelsAnnouncement() {
+        this.removeBannerElement(OTHER_MODELS_BANNER_ID);
+    }
+
     initializeCommunitySupportState() {
         const storedVersion = getStorageItem(COMMUNITY_SUPPORT_VERSION_KEY, null);