feat(storefront): homepage, module gating, widget protocol, i18n fixes

Storefront homepage & module gating:
- CMS owns storefront GET / (slug="home" with 3-tier resolution)
- Catalog loses GET / (keeps /products only)
- Store root redirect (GET / → /store/dashboard or /store/login)
- Route gating: non-core modules return 404 when disabled for platform
- Seed store default homepages per platform

Widget protocol for customer dashboard:
- StorefrontDashboardCard contract in widgets.py
- Widget aggregator get_storefront_dashboard_cards()
- Orders and Loyalty module widget providers
- Dashboard template renders contributed cards (no module names)

Landing template module-agnostic:
- CTAs driven by storefront_nav (not hardcoded module names)
- Header actions check nav item IDs (not enabled_modules)
- Remove hardcoded "Add Product" sidebar button
- Remove all enabled_modules checks from storefront templates

i18n fixes:
- Title placeholder resolution ({{store_name}}) for store default pages
- Storefront nav label_keys prefixed with module code
- Add storefront.account.* keys to 6 modules (en/fr/de/lb)
- Header/footer CMS pages use get_translated_title(current_language)
- Footer labels use i18n keys instead of hardcoded English

Icon cleanup:
- Standardize on map-pin (remove location-marker alias)
- Replace all location-marker references across templates and docs

Docs:
- Storefront builder vision proposal (6 phases)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

static/shared/js/icons.js

@@ -118,7 +118,7 @@ const Icons = {
     'color-swatch': `<svg class="{{classes}}" fill="none" stroke="currentColor" viewBox="0 0 24 24"><path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M7 21a4 4 0 01-4-4V5a2 2 0 012-2h4a2 2 0 012 2v12a4 4 0 01-4 4zm0 0h12a2 2 0 002-2v-4a2 2 0 00-2-2h-2.343M11 7.343l1.657-1.657a2 2 0 012.828 0l2.829 2.829a2 2 0 010 2.828l-8.486 8.485M7 17h.01"/></svg>`,
 
     // Location
-    'location-marker': `<svg class="{{classes}}" fill="none" stroke="currentColor" viewBox="0 0 24 24"><path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M17.657 16.657L13.414 20.9a1.998 1.998 0 01-2.827 0l-4.244-4.243a8 8 0 1111.314 0z"/><path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M15 11a3 3 0 11-6 0 3 3 0 016 0z"/></svg>`,
+    'map-pin': `<svg class="{{classes}}" fill="none" stroke="currentColor" viewBox="0 0 24 24"><path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M17.657 16.657L13.414 20.9a1.998 1.998 0 01-2.827 0l-4.244-4.243a8 8 0 1111.314 0z"/><path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M15 11a3 3 0 11-6 0 3 3 0 016 0z"/></svg>`,
     'globe': `<svg class="{{classes}}" fill="none" stroke="currentColor" viewBox="0 0 24 24"><path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M3.055 11H5a2 2 0 012 2v1a2 2 0 002 2 2 2 0 012 2v2.945M8 3.935V5.5A2.5 2.5 0 0010.5 8h.5a2 2 0 012 2 2 2 0 104 0 2 2 0 012-2h1.064M15 20.488V18a2 2 0 012-2h3.064M21 12a9 9 0 11-18 0 9 9 0 0118 0z"/></svg>`,
     'globe-alt': `<svg class="{{classes}}" fill="none" stroke="currentColor" viewBox="0 0 24 24"><path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M21 12a9 9 0 01-9 9m9-9a9 9 0 00-9-9m9 9H3m9 9a9 9 0 01-9-9m9 9c1.657 0 3-4.03 3-9s-1.343-9-3-9m0 18c-1.657 0-3-4.03-3-9s1.343-9 3-9m-9 9a9 9 0 019-9"/></svg>`,