removing legacy code on path_rewrite_middleware

docs/architecture/request-flow.md

@@ -112,25 +112,29 @@ request.state.vendor_id = 1
 request.state.clean_path = "/shop/products"
 ```
 
-### 4. PathRewriteMiddleware
+### 4. Router Matching (FastAPI Native)
 
 **What happens**:
-- Checks if `clean_path` is different from original path
-- If different, rewrites the request path for FastAPI routing
+- FastAPI matches the request path against registered routes
+- For path-based development mode, routes are registered with two prefixes:
+  - `/shop/*` for subdomain/custom domain
+  - `/vendors/{vendor_code}/shop/*` for path-based development
 
 **Example** (Path-Based Mode):
 
 ```python
-# Input (path-based development mode)
-original_path = "/vendors/WIZAMART/shop/products"
-clean_path = "/shop/products"  # From VendorContextMiddleware
+# In main.py - Double router mounting
+app.include_router(shop_pages.router, prefix="/shop")
+app.include_router(shop_pages.router, prefix="/vendors/{vendor_code}/shop")
 
-# Path rewrite
-if clean_path != original_path:
-    request.scope['path'] = clean_path
-    request._url = request.url.replace(path=clean_path)
+# Request: /vendors/WIZAMART/shop/products
+# Matches: Second router (/vendors/{vendor_code}/shop)
+# Route: @router.get("/products")
+# vendor_code available as path parameter = "WIZAMART"
 ```
 
+**Note:** Previous implementations used `PathRewriteMiddleware` to rewrite paths. This has been replaced with FastAPI's native routing via double router mounting.
+
 **Request State After**: No changes to state, but internal path updated
 
 ### 5. ContextDetectionMiddleware