feat: multi-module improvements across merchant, store, i18n, and customer systems

- Fix platform-grouped merchant sidebar menu with core items at root level
- Add merchant store management (detail page, create store, team page)
- Fix store settings 500 error by removing dead stripe/API tab
- Move onboarding translations to module-owned locale files
- Fix onboarding banner i18n with server-side rendering + context inheritance
- Refactor login language selectors to use languageSelector() function (LANG-002)
- Move HTTPException handling to global exception handler in merchant routes (API-003)
- Add language selector to all login pages and portal headers
- Fix customer module: drop order stats from customer model, add to orders module
- Fix admin menu config visibility for super admin platform context
- Fix storefront auth and layout issues
- Add missing i18n translations for onboarding steps (en/fr/de/lb)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/modules/tenancy/static/admin/js/select-platform.js

@@ -1,5 +1,5 @@
 // static/admin/js/select-platform.js
-// Platform selection page for platform admins
+// Platform selection page for admins (platform admins and super admins)
 
 const platformLog = window.LogConfig ? window.LogConfig.createLogger('PLATFORM_SELECT') : console;
 
@@ -11,6 +11,7 @@ function selectPlatform() {
         error: null,
         platforms: [],
         isSuperAdmin: false,
+        currentPlatformId: null,
 
         async init() {
             platformLog.info('=== PLATFORM SELECTION PAGE INITIALIZING ===');
@@ -46,21 +47,14 @@ function selectPlatform() {
                 const response = await apiClient.get('/admin/auth/accessible-platforms');
                 platformLog.debug('Platforms response:', response);
 
-                this.isSuperAdmin = response.role === 'super_admin';
+                this.isSuperAdmin = response.is_super_admin === true;
                 this.platforms = response.platforms || [];
+                this.currentPlatformId = response.current_platform_id || null;
 
-                if (this.isSuperAdmin) {
-                    platformLog.info('User is super admin, redirecting to dashboard...');
-                    setTimeout(() => {
-                        window.location.href = '/admin/dashboard';
-                    }, 1500);
-                    return;
-                }
-
-                if (!response.requires_platform_selection && this.platforms.length === 1) {
+                if (!this.isSuperAdmin && !response.requires_platform_selection && this.platforms.length === 1) {
                     // Only one platform assigned, auto-select it
                     platformLog.info('Single platform assigned, auto-selecting...');
-                    await this.selectPlatform(this.platforms[0]);
+                    await this.choosePlatform(this.platforms[0]);
                     return;
                 }
 
@@ -81,7 +75,11 @@ function selectPlatform() {
             }
         },
 
-        async selectPlatform(platform) {
+        isCurrentPlatform(platform) {
+            return this.currentPlatformId && this.currentPlatformId === platform.id;
+        },
+
+        async choosePlatform(platform) {
             if (this.selecting) return;
 
             this.selecting = true;
@@ -132,6 +130,37 @@ function selectPlatform() {
             }
         },
 
+        async deselectPlatform() {
+            if (this.selecting) return;
+
+            this.selecting = true;
+            this.error = null;
+            platformLog.info('Deselecting platform (returning to global mode)...');
+
+            try {
+                const response = await apiClient.post('/admin/auth/deselect-platform');
+
+                if (response.access_token) {
+                    // Store new token without platform context
+                    localStorage.setItem('admin_token', response.access_token);
+                    localStorage.setItem('token', response.access_token);
+
+                    // Remove platform info
+                    localStorage.removeItem('admin_platform');
+
+                    platformLog.info('Platform deselected, redirecting to dashboard...');
+                    window.location.href = '/admin/dashboard';
+                } else {
+                    throw new Error('No token received from server');
+                }
+
+            } catch (error) {
+                platformLog.error('Platform deselection failed:', error);
+                this.error = error.message || 'Failed to deselect platform. Please try again.';
+                this.selecting = false;
+            }
+        },
+
         async logout() {
             platformLog.info('Logging out...');
 

app/modules/tenancy/static/store/js/login.js

@@ -8,6 +8,27 @@
 // Create custom logger for store login page
 const storeLoginLog = window.LogConfig.createLogger('STORE-LOGIN');
 
+function languageSelector(currentLang, enabledLanguages) {
+    return {
+        currentLang: currentLang || 'fr',
+        languages: enabledLanguages || ['en', 'fr', 'de', 'lb'],
+        async setLanguage(lang) {
+            if (lang === this.currentLang) return;
+            try {
+                // noqa: JS-008 - Login page has no apiClient; raw fetch is intentional
+                await fetch('/api/v1/platform/language/set', {
+                    method: 'POST',
+                    headers: { 'Content-Type': 'application/json' },
+                    body: JSON.stringify({ language: lang }),
+                });
+                window.location.reload();
+            } catch (error) {
+                storeLoginLog.error('Failed to set language:', error);
+            }
+        },
+    };
+}
+
 function storeLogin() {
     return {
         credentials: {
@@ -159,6 +180,7 @@ function storeLogin() {
         },
 
         // Forgot password state
+        rememberMe: false,
         showForgotPassword: false,
         forgotPasswordEmail: '',
         forgotPasswordLoading: false,

app/modules/tenancy/static/store/js/settings.js

@@ -39,7 +39,6 @@ function storeSettings() {
             { id: 'invoices', label: 'Invoices', icon: 'document-text' },
             { id: 'branding', label: 'Branding', icon: 'color-swatch' },
             { id: 'domains', label: 'Domains', icon: 'globe-alt' },
-            { id: 'api', label: 'API & Payments', icon: 'key' },
             { id: 'notifications', label: 'Notifications', icon: 'bell' },
             { id: 'email', label: 'Email', icon: 'mail' }
         ],