docs: add nav fix to POC content mapping proposal

E-commerce nav (Products, Cart, Account) shows on hosting POC sites.
Preview mode should render only CMS pages (Services, Projects, Contact)
in the nav, not module-defined e-commerce items.

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

docs/proposals/poc-content-mapping.md

@@ -137,7 +137,38 @@ When `request.state.is_preview` is True, render social links from the store's CM
 | `cms/storefront/landing-full.html` | Ensure gallery section renders |
 | Template JSON files | Add `{{hero_subtitle}}`, `{{hero_image}}` placeholders |
 
+## Additional Issue: Storefront Navigation
+
+The storefront base template shows e-commerce navigation (Products, Cart, Account) which makes no sense for a hosting POC (construction company showing "Products" in the menu).
+
+**Fix options:**
+1. **Platform-aware nav** — the hosting platform should have its own storefront base template (or at minimum, a nav override) that hides e-commerce menus and only shows CMS pages
+2. **CMS-only nav for POC** — when `is_preview` is True, render navigation only from the store's published CMS pages (`show_in_header=True`), not from module-defined nav items
+3. **Storefront nav config per platform** — each platform defines which nav items are visible (hosting = CMS pages only, OMS = full e-commerce, loyalty = loyalty-specific)
+
+**Recommended: Option 2** — simplest, preview-specific. In `storefront/base.html`, when `request.state.is_preview`, replace the entire nav with links to CMS pages:
+
+```html
+{% if request.state.is_preview|default(false) %}
+    {# Preview mode: show only CMS pages, no e-commerce nav #}
+    {% for page in header_pages %}
+        <a href="{{ base_url }}{{ page.slug }}">{{ page.title }}</a>
+    {% endfor %}
+{% else %}
+    {# Normal storefront nav #}
+    ... existing e-commerce nav ...
+{% endif %}
+```
+
+The `header_pages` variable is already populated from CMS ContentPages where `show_in_header=True`.
+
+## Files to modify (navigation fix)
+
+| File | Change |
+|---|---|
+| `app/templates/storefront/base.html` | Wrap main nav in `is_preview` check, show CMS-only nav in preview mode |
+
 ## Estimated effort
 
-- Phase 1 (programmatic): ~2-3 hours
+- Phase 1 (programmatic content mapping + nav fix): ~3-4 hours
 - Phase 2 (AI): depends on provider integration (deferred)