fix(ui): inject window.FRONTEND_TYPE from server + rename SHOP→STOREFRONT

Server now injects window.FRONTEND_TYPE in all base templates via
get_context_for_frontend(). Both log-config.js and dev-toolbar.js read
this instead of guessing from URL paths, fixing:
- UNKNOWN prefix on merchant pages
- Incorrect detection on custom domains/subdomains in prod

Also adds frontend_type to login page contexts (admin, merchant, store).

Renames all [SHOP] logger prefixes to [STOREFRONT] across 7 files
(storefront-layout.js + 6 storefront templates).

Adds 'merchant' and 'storefront' to log-config.js frontend detection,
log levels, and logger selection.

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

app/modules/core/utils/page_context.py

@@ -149,6 +149,9 @@ def get_context_for_frontend(
     # Pass enabled module codes to templates for conditional rendering
     context["enabled_modules"] = enabled_module_codes
 
+    # Pass frontend type to templates (used by JS for logging, dev toolbar, etc.)
+    context["frontend_type"] = frontend_type.value
+
     # For storefront, build nav menu structure from module declarations
     if frontend_type == FrontendType.STOREFRONT:
         from app.modules.core.services.menu_discovery_service import (