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/auto-parts/meta.json

@@ -0,0 +1 @@
+{"id": "auto-parts", "name": "Auto Parts & Garage", "description": "Template for auto parts shops, garages, and car dealers", "tags": ["automotive", "garage", "car", "parts"], "languages": ["en", "fr", "de"]}

app/modules/hosting/templates_library/auto-parts/pages/catalog.json

@@ -0,0 +1,12 @@
+{
+  "slug": "catalog",
+  "title": "Catalog",
+  "title_translations": {"en": "Parts Catalog", "fr": "Catalogue de pièces", "de": "Teilekatalog"},
+  "template": "default",
+  "is_published": true,
+  "show_in_header": true,
+  "content_translations": {
+    "en": "<h2>Parts Catalog</h2>\n<p>Browse our extensive catalog of auto parts for all major brands.</p>",
+    "fr": "<h2>Catalogue de pièces</h2>\n<p>Parcourez notre catalogue complet de pièces auto pour toutes les grandes marques.</p>"
+  }
+}

app/modules/hosting/templates_library/auto-parts/pages/contact.json

@@ -0,0 +1,13 @@
+{
+  "slug": "contact",
+  "title": "Contact",
+  "title_translations": {"en": "Contact Us", "fr": "Contactez-nous", "de": "Kontakt"},
+  "template": "default",
+  "is_published": true,
+  "show_in_header": true,
+  "show_in_footer": true,
+  "content_translations": {
+    "en": "<h2>Contact Us</h2>\n<p>Visit our store or get in touch for parts inquiries.</p>\n<ul>\n<li>Phone: {{phone}}</li>\n<li>Email: {{email}}</li>\n<li>Address: {{address}}</li>\n</ul>",
+    "fr": "<h2>Contactez-nous</h2>\n<p>Visitez notre magasin ou contactez-nous pour vos demandes de pièces.</p>\n<ul>\n<li>Téléphone : {{phone}}</li>\n<li>Email : {{email}}</li>\n<li>Adresse : {{address}}</li>\n</ul>"
+  }
+}

app/modules/hosting/templates_library/auto-parts/pages/homepage.json

@@ -0,0 +1,34 @@
+{
+  "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": "Your trusted auto parts specialist in {{city}}", "fr": "Votre spécialiste pièces auto de confiance à {{city}}"}},
+      "background_type": "image",
+      "buttons": [
+        {"label": {"translations": {"en": "Browse Parts", "fr": "Voir les pièces"}}, "url": "/catalog", "style": "primary"},
+        {"label": {"translations": {"en": "Contact Us", "fr": "Contactez-nous"}}, "url": "/contact", "style": "secondary"}
+      ]
+    },
+    "features": {
+      "enabled": true,
+      "title": {"translations": {"en": "Why Choose Us", "fr": "Pourquoi nous choisir"}},
+      "items": [
+        {"icon": "truck", "title": {"translations": {"en": "Fast Delivery", "fr": "Livraison rapide"}}, "description": {"translations": {"en": "Same-day delivery on in-stock parts", "fr": "Livraison le jour même pour les pièces en stock"}}},
+        {"icon": "shield-check", "title": {"translations": {"en": "Quality Guaranteed", "fr": "Qualité garantie"}}, "description": {"translations": {"en": "OEM and certified aftermarket parts", "fr": "Pièces OEM et aftermarket certifiées"}}},
+        {"icon": "currency-euro", "title": {"translations": {"en": "Best Prices", "fr": "Meilleurs prix"}}, "description": {"translations": {"en": "Competitive pricing on all brands", "fr": "Prix compétitifs sur toutes les marques"}}}
+      ]
+    },
+    "cta": {
+      "enabled": true,
+      "title": {"translations": {"en": "Need a specific part?", "fr": "Besoin d'une pièce spécifique ?"}},
+      "buttons": [
+        {"label": {"translations": {"en": "Contact Us", "fr": "Contactez-nous"}}, "url": "/contact", "style": "primary"}
+      ]
+    }
+  }
+}

app/modules/hosting/templates_library/auto-parts/theme.json

@@ -0,0 +1,8 @@
+{
+  "theme_name": "modern",
+  "colors": {"primary": "#dc2626", "secondary": "#991b1b", "accent": "#f59e0b", "background": "#fafafa", "text": "#18181b", "border": "#e4e4e7"},
+  "font_family_heading": "Montserrat",
+  "font_family_body": "Inter",
+  "layout_style": "grid",
+  "header_style": "fixed"
+}