feat(hosting): add HostWizard platform module and fix migration chain

- Add complete hosting module (models, routes, schemas, services, templates, migrations)
- Add HostWizard platform to init_production seed (code=hosting, domain=hostwizard.lu)
- Fix cms_002 migration down_revision to z_unique_subdomain_domain
- Fix prospecting_001 migration to chain after cms_002 (remove branch label)
- Add hosting/prospecting version_locations to alembic.ini
- Fix admin_services delete endpoint to use proper response model
- Add hostwizard.lu to deployment docs (DNS, Caddy, Cloudflare)
- Add hosting and prospecting user journey docs to mkdocs nav

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

app/modules/hosting/routes/pages/public.py

@@ -0,0 +1,46 @@
+# app/modules/hosting/routes/pages/public.py
+"""
+Hosting Public Page Routes.
+
+Public-facing routes for POC site viewing:
+- POC Viewer - Shows the Store's storefront with a HostWizard preview banner
+"""
+
+from fastapi import APIRouter, Depends, Path, Request
+from fastapi.responses import HTMLResponse
+from sqlalchemy.orm import Session
+
+from app.core.database import get_db
+from app.templates_config import templates
+
+router = APIRouter()
+
+
+@router.get(
+    "/hosting/sites/{site_id}/preview",
+    response_class=HTMLResponse,
+    include_in_schema=False,
+)
+async def poc_site_viewer(
+    request: Request,
+    site_id: int = Path(..., description="Hosted Site ID"),
+    db: Session = Depends(get_db),
+):
+    """Render POC site viewer with HostWizard preview banner."""
+    from app.modules.hosting.models import HostedSite, HostedSiteStatus
+
+    site = db.query(HostedSite).filter(HostedSite.id == site_id).first()
+
+    # Only allow viewing for poc_ready or proposal_sent sites
+    if not site or site.status not in (HostedSiteStatus.POC_READY, HostedSiteStatus.PROPOSAL_SENT):
+        return HTMLResponse(content="<h1>Site not available for preview</h1>", status_code=404)
+
+    context = {
+        "request": request,
+        "site": site,
+        "store_url": f"/stores/{site.store.subdomain}" if site.store else "#",
+    }
+    return templates.TemplateResponse(
+        "hosting/public/poc-viewer.html",
+        context,
+    )