docs: Update all documentation for standalone mode and settings structure

SPA_ADMIN_MENU_PLAN.md

@@ -182,7 +182,9 @@ Marketing
 
 
 ## Proposed SPA Main Menu (Authoritative)
-This replaces wp‑admin’s structure with a focused SPA hierarchy. Analytics & Marketing are folded into **Dashboard**. **Status** and **Extensions** live under **Settings**.
+This replaces wp‑admin's structure with a focused SPA hierarchy. Analytics & Marketing are folded into **Dashboard**. **Status** and **Extensions** live under **Settings**.
+
+**Note:** Settings submenu is **only visible in Standalone Mode** (`/admin`). In normal wp-admin mode, users access WooCommerce settings through the standard WordPress admin interface.
 
 ```text
 Dashboard
@@ -214,18 +216,19 @@ Customers
 └── All Customers (/customers)
   (Customers are derived from orders + user profiles; non‑buyers are excluded by default.)
 
-Settings
-├── General (/settings/general)
-├── Products (/settings/products)
-├── Tax (/settings/tax)
-├── Shipping (/settings/shipping)
-├── Payments (/settings/payments)
-├── Accounts & Privacy (/settings/accounts)
-├── Emails (/settings/emails)
-├── Integrations (/settings/integrations)
-├── Advanced (/settings/advanced)
-├── Status (/settings/status)
-└── Extensions (/settings/extensions)
+Settings (Standalone Mode Only)
+├── WooNooW (/settings)                      ← plugin settings
+├── General (/settings/general)              ← SPA
+├── Payments (/settings/payments)            ← SPA
+├── Shipping (/settings/shipping)            ← SPA
+├── Products (/settings/products)            ← SPA
+├── Tax (/settings/tax)                      ← SPA
+├── Accounts & Privacy (/settings/accounts)  ← SPA
+├── Emails (/settings/emails)                ← SPA
+├── Advanced (bridge to wp-admin)            ← Bridge
+├── Integration (bridge to wp-admin)         ← Bridge
+├── Status (bridge to wp-admin)              ← Bridge
+└── Extensions (bridge to wp-admin)          ← Bridge
 ```
 
 ### Routing notes