feat(hosting): add industry template infrastructure (Workstream 3B)

5 industry templates as JSON presets, each with theme + multi-page content:
- generic: clean minimal (homepage, about, contact)
- restaurant: warm tones, Playfair Display (homepage, about, menu, contact)
- construction: amber/earth tones, Montserrat (homepage, services, projects, contact)
- auto-parts: red/bold, parts-focused (homepage, catalog, contact)
- professional-services: navy/blue, Merriweather (homepage, services, team, contact)

Each template has:
- meta.json (name, description, tags, languages)
- theme.json (colors, fonts, layout, header style)
- pages/*.json (section-based homepage + content pages with i18n)
- {{placeholder}} variables for prospect data injection

TemplateService loads from templates_library/ directory with caching.
GET /admin/hosting/sites/templates endpoint to list available templates.

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

app/modules/hosting/templates_library/restaurant/pages/homepage.json

@@ -0,0 +1,39 @@
+{
+  "slug": "homepage",
+  "title": "{{business_name}}",
+  "template": "full",
+  "is_published": true,
+  "sections": {
+    "hero": {
+      "enabled": true,
+      "title": {"translations": {"en": "{{business_name}}", "fr": "{{business_name}}"}},
+      "subtitle": {"translations": {"en": "A culinary experience in {{city}}", "fr": "Une expérience culinaire à {{city}}"}},
+      "background_type": "image",
+      "buttons": [
+        {"label": {"translations": {"en": "Reserve a Table", "fr": "Réserver une table"}}, "url": "/contact", "style": "primary"},
+        {"label": {"translations": {"en": "See Our Menu", "fr": "Voir la carte"}}, "url": "/menu", "style": "secondary"}
+      ]
+    },
+    "features": {
+      "enabled": true,
+      "title": {"translations": {"en": "Our Specialties", "fr": "Nos Spécialités"}},
+      "items": [
+        {"icon": "fire", "title": {"translations": {"en": "Fresh Ingredients", "fr": "Produits frais"}}, "description": {"translations": {"en": "Locally sourced, seasonal ingredients", "fr": "Produits locaux et de saison"}}},
+        {"icon": "star", "title": {"translations": {"en": "Chef's Selection", "fr": "Sélection du chef"}}, "description": {"translations": {"en": "Carefully crafted dishes by our expert chef", "fr": "Plats élaborés par notre chef expert"}}},
+        {"icon": "heart", "title": {"translations": {"en": "Warm Atmosphere", "fr": "Ambiance chaleureuse"}}, "description": {"translations": {"en": "A welcoming space for every occasion", "fr": "Un espace accueillant pour chaque occasion"}}}
+      ]
+    },
+    "testimonials": {
+      "enabled": true,
+      "title": {"translations": {"en": "What Our Guests Say", "fr": "Ce que disent nos clients"}},
+      "items": []
+    },
+    "cta": {
+      "enabled": true,
+      "title": {"translations": {"en": "Ready to dine with us?", "fr": "Prêt à nous rendre visite ?"}},
+      "buttons": [
+        {"label": {"translations": {"en": "Make a Reservation", "fr": "Réserver"}}, "url": "/contact", "style": "primary"}
+      ]
+    }
+  }
+}