refactor: migrate templates and static files to self-contained modules

Templates Migration:
- Migrate admin templates to modules (tenancy, billing, monitoring, marketplace, etc.)
- Migrate vendor templates to modules (tenancy, billing, orders, messaging, etc.)
- Migrate storefront templates to modules (catalog, customers, orders, cart, checkout, cms)
- Migrate public templates to modules (billing, marketplace, cms)
- Keep shared templates in app/templates/ (base.html, errors/, partials/, macros/)
- Migrate letzshop partials to marketplace module

Static Files Migration:
- Migrate admin JS to modules: tenancy (23 files), core (5 files), monitoring (1 file)
- Migrate vendor JS to modules: tenancy (4 files), core (2 files)
- Migrate shared JS: vendor-selector.js to core, media-picker.js to cms
- Migrate storefront JS: storefront-layout.js to core
- Keep framework JS in static/ (api-client, utils, money, icons, log-config, lib/)
- Update all template references to use module_static paths

Naming Consistency:
- Rename static/platform/ to static/public/
- Rename app/templates/platform/ to app/templates/public/
- Update all extends and static references

Documentation:
- Update module-system.md with shared templates documentation
- Update frontend-structure.md with new module JS organization

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

app/modules/tenancy/routes/pages/vendor.py

@@ -0,0 +1,156 @@
+# app/modules/tenancy/routes/pages/vendor.py
+"""
+Tenancy Vendor Page Routes (HTML rendering).
+
+Vendor pages for authentication and account management:
+- Root redirect
+- Login
+- Team management
+- Profile
+- Settings
+"""
+
+from fastapi import APIRouter, Depends, Path, Request
+from fastapi.responses import HTMLResponse, RedirectResponse
+from sqlalchemy.orm import Session
+
+from app.api.deps import (
+    get_current_vendor_from_cookie_or_header,
+    get_current_vendor_optional,
+    get_db,
+)
+from app.modules.core.utils.page_context import get_vendor_context
+from app.templates_config import templates
+from models.database.user import User
+
+router = APIRouter()
+
+
+# ============================================================================
+# PUBLIC ROUTES (No Authentication Required)
+# ============================================================================
+
+
+@router.get("/{vendor_code}", response_class=RedirectResponse, include_in_schema=False)
+async def vendor_root_no_slash(vendor_code: str = Path(..., description="Vendor code")):
+    """
+    Redirect /vendor/{code} (no trailing slash) to login page.
+    Handles requests without trailing slash.
+    """
+    return RedirectResponse(url=f"/vendor/{vendor_code}/login", status_code=302)
+
+
+@router.get(
+    "/{vendor_code}/", response_class=RedirectResponse, include_in_schema=False
+)
+async def vendor_root(
+    vendor_code: str = Path(..., description="Vendor code"),
+    current_user: User | None = Depends(get_current_vendor_optional),
+):
+    """
+    Redirect /vendor/{code}/ based on authentication status.
+
+    - Authenticated vendor users -> /vendor/{code}/dashboard
+    - Unauthenticated users -> /vendor/{code}/login
+    """
+    if current_user:
+        return RedirectResponse(
+            url=f"/vendor/{vendor_code}/dashboard", status_code=302
+        )
+
+    return RedirectResponse(url=f"/vendor/{vendor_code}/login", status_code=302)
+
+
+@router.get(
+    "/{vendor_code}/login", response_class=HTMLResponse, include_in_schema=False
+)
+async def vendor_login_page(
+    request: Request,
+    vendor_code: str = Path(..., description="Vendor code"),
+    current_user: User | None = Depends(get_current_vendor_optional),
+):
+    """
+    Render vendor login page.
+
+    If user is already authenticated as vendor, redirect to dashboard.
+    Otherwise, show login form.
+
+    JavaScript will:
+    - Load vendor info via API
+    - Handle login form submission
+    - Redirect to dashboard on success
+    """
+    if current_user:
+        return RedirectResponse(
+            url=f"/vendor/{vendor_code}/dashboard", status_code=302
+        )
+
+    return templates.TemplateResponse(
+        "tenancy/vendor/login.html",
+        {
+            "request": request,
+            "vendor_code": vendor_code,
+        },
+    )
+
+
+# ============================================================================
+# AUTHENTICATED ROUTES (Vendor Users Only)
+# ============================================================================
+
+
+@router.get(
+    "/{vendor_code}/team", response_class=HTMLResponse, include_in_schema=False
+)
+async def vendor_team_page(
+    request: Request,
+    vendor_code: str = Path(..., description="Vendor code"),
+    current_user: User = Depends(get_current_vendor_from_cookie_or_header),
+    db: Session = Depends(get_db),
+):
+    """
+    Render team management page.
+    JavaScript loads team members via API.
+    """
+    return templates.TemplateResponse(
+        "tenancy/vendor/team.html",
+        get_vendor_context(request, db, current_user, vendor_code),
+    )
+
+
+@router.get(
+    "/{vendor_code}/profile", response_class=HTMLResponse, include_in_schema=False
+)
+async def vendor_profile_page(
+    request: Request,
+    vendor_code: str = Path(..., description="Vendor code"),
+    current_user: User = Depends(get_current_vendor_from_cookie_or_header),
+    db: Session = Depends(get_db),
+):
+    """
+    Render vendor profile page.
+    User can manage their personal profile information.
+    """
+    return templates.TemplateResponse(
+        "tenancy/vendor/profile.html",
+        get_vendor_context(request, db, current_user, vendor_code),
+    )
+
+
+@router.get(
+    "/{vendor_code}/settings", response_class=HTMLResponse, include_in_schema=False
+)
+async def vendor_settings_page(
+    request: Request,
+    vendor_code: str = Path(..., description="Vendor code"),
+    current_user: User = Depends(get_current_vendor_from_cookie_or_header),
+    db: Session = Depends(get_db),
+):
+    """
+    Render vendor settings page.
+    JavaScript loads settings via API.
+    """
+    return templates.TemplateResponse(
+        "tenancy/vendor/settings.html",
+        get_vendor_context(request, db, current_user, vendor_code),
+    )