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/generic/meta.json

@@ -0,0 +1,7 @@
+{
+  "id": "generic",
+  "name": "Generic Business",
+  "description": "Clean, minimal template that works for any business type",
+  "tags": ["general", "minimal", "any"],
+  "languages": ["en", "fr", "de"]
+}

app/modules/hosting/templates_library/generic/pages/about.json

@@ -0,0 +1,13 @@
+{
+  "slug": "about",
+  "title": "About Us",
+  "title_translations": {"en": "About Us", "fr": "À propos", "de": "Über uns"},
+  "template": "default",
+  "is_published": true,
+  "show_in_header": true,
+  "content": "{{about_content}}",
+  "content_translations": {
+    "en": "<h2>About {{business_name}}</h2>\n<p>{{about_paragraph}}</p>",
+    "fr": "<h2>À propos de {{business_name}}</h2>\n<p>{{about_paragraph}}</p>"
+  }
+}

app/modules/hosting/templates_library/generic/pages/contact.json

@@ -0,0 +1,13 @@
+{
+  "slug": "contact",
+  "title": "Contact",
+  "title_translations": {"en": "Contact Us", "fr": "Contact", "de": "Kontakt"},
+  "template": "default",
+  "is_published": true,
+  "show_in_header": true,
+  "show_in_footer": true,
+  "content_translations": {
+    "en": "<h2>Get in Touch</h2>\n<p>We'd love to hear from you. Reach out using the information below.</p>\n<ul>\n<li>Email: {{email}}</li>\n<li>Phone: {{phone}}</li>\n<li>Address: {{address}}</li>\n</ul>",
+    "fr": "<h2>Contactez-nous</h2>\n<p>N'hésitez pas à nous contacter.</p>\n<ul>\n<li>Email : {{email}}</li>\n<li>Téléphone : {{phone}}</li>\n<li>Adresse : {{address}}</li>\n</ul>"
+  }
+}

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

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+{
+  "slug": "homepage",
+  "title": "{{business_name}}",
+  "template": "full",
+  "is_published": true,
+  "show_in_header": false,
+  "sections": {
+    "hero": {
+      "enabled": true,
+      "title": {"translations": {"en": "{{business_name}}", "fr": "{{business_name}}"}},
+      "subtitle": {"translations": {"en": "{{meta_description}}", "fr": "{{meta_description}}"}},
+      "background_type": "gradient",
+      "buttons": [
+        {"label": {"translations": {"en": "Contact Us", "fr": "Contactez-nous"}}, "url": "/contact", "style": "primary"}
+      ]
+    },
+    "features": {
+      "enabled": true,
+      "title": {"translations": {"en": "What We Offer", "fr": "Nos Services"}},
+      "items": [
+        {"icon": "shield-check", "title": {"translations": {"en": "Quality", "fr": "Qualité"}}, "description": {"translations": {"en": "Committed to excellence in everything we do", "fr": "Engagés pour l'excellence dans tout ce que nous faisons"}}},
+        {"icon": "clock", "title": {"translations": {"en": "Reliability", "fr": "Fiabilité"}}, "description": {"translations": {"en": "Dependable service you can count on", "fr": "Un service fiable sur lequel vous pouvez compter"}}},
+        {"icon": "users", "title": {"translations": {"en": "Experience", "fr": "Expérience"}}, "description": {"translations": {"en": "Years of expertise at your service", "fr": "Des années d'expertise à votre service"}}}
+      ]
+    },
+    "cta": {
+      "enabled": true,
+      "title": {"translations": {"en": "Ready to get started?", "fr": "Prêt à commencer ?"}},
+      "subtitle": {"translations": {"en": "Contact us today for a free consultation", "fr": "Contactez-nous pour une consultation gratuite"}},
+      "buttons": [
+        {"label": {"translations": {"en": "Get in Touch", "fr": "Nous Contacter"}}, "url": "/contact", "style": "primary"}
+      ]
+    }
+  }
+}

app/modules/hosting/templates_library/generic/theme.json

@@ -0,0 +1,15 @@
+{
+  "theme_name": "modern",
+  "colors": {
+    "primary": "#3b82f6",
+    "secondary": "#1e40af",
+    "accent": "#f59e0b",
+    "background": "#ffffff",
+    "text": "#1e293b",
+    "border": "#e2e8f0"
+  },
+  "font_family_heading": "Inter",
+  "font_family_body": "Inter",
+  "layout_style": "grid",
+  "header_style": "fixed"
+}