refactor: switch to full auto-discovery for module API routes

- Enhanced route discovery system with ROUTE_CONFIG support for custom
  prefix, tags, and priority
- Added get_admin_api_routes() and get_vendor_api_routes() helpers that
  return routes sorted by priority
- Added fallback discovery for routes/{frontend}.py when routes/api/
  doesn't exist
- Updated CMS module with ROUTE_CONFIG (prefix: /content-pages,
  priority: 100) to register last for catch-all routes
- Moved customers routes from routes/ to routes/api/ directory
- Updated orders module to aggregate exception routers into main routers
- Removed manual module router imports from admin and vendor API init
  files, replaced with auto-discovery loop

Modules now auto-discovered: billing, inventory, orders, marketplace,
cms, customers, analytics, loyalty, messaging, monitoring, dev-tools

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

app/modules/customers/routes/api/admin.py

@@ -0,0 +1,122 @@
+# app/modules/customers/routes/api/admin.py
+"""
+Customer management endpoints for admin.
+
+Provides admin-level access to customer data across all vendors.
+"""
+
+from fastapi import APIRouter, Depends, Query
+from sqlalchemy.orm import Session
+
+from app.api.deps import get_current_admin_api, require_module_access
+from app.core.database import get_db
+from app.modules.customers.services import admin_customer_service
+from models.schema.auth import UserContext
+from app.modules.customers.schemas import (
+    CustomerDetailResponse,
+    CustomerListResponse,
+    CustomerMessageResponse,
+    CustomerStatisticsResponse,
+)
+
+# Create module-aware router
+admin_router = APIRouter(
+    prefix="/customers",
+    dependencies=[Depends(require_module_access("customers"))],
+)
+
+
+# ============================================================================
+# List Customers
+# ============================================================================
+
+
+@admin_router.get("", response_model=CustomerListResponse)
+def list_customers(
+    vendor_id: int | None = Query(None, description="Filter by vendor ID"),
+    search: str = Query("", description="Search by email, name, or customer number"),
+    is_active: bool | None = Query(None, description="Filter by active status"),
+    skip: int = Query(0, ge=0),
+    limit: int = Query(20, ge=1, le=100),
+    db: Session = Depends(get_db),
+    current_admin: UserContext = Depends(get_current_admin_api),
+) -> CustomerListResponse:
+    """
+    Get paginated list of customers across all vendors.
+
+    Admin can filter by vendor, search, and active status.
+    """
+    customers, total = admin_customer_service.list_customers(
+        db=db,
+        vendor_id=vendor_id,
+        search=search if search else None,
+        is_active=is_active,
+        skip=skip,
+        limit=limit,
+    )
+
+    # Calculate pagination values
+    page = (skip // limit) + 1 if limit > 0 else 1
+    per_page = limit
+    total_pages = (total + limit - 1) // limit if limit > 0 else 1
+
+    return CustomerListResponse(
+        customers=customers,
+        total=total,
+        page=page,
+        per_page=per_page,
+        total_pages=total_pages,
+    )
+
+
+# ============================================================================
+# Customer Statistics
+# ============================================================================
+
+
+@admin_router.get("/stats", response_model=CustomerStatisticsResponse)
+def get_customer_stats(
+    vendor_id: int | None = Query(None, description="Filter by vendor ID"),
+    db: Session = Depends(get_db),
+    current_admin: UserContext = Depends(get_current_admin_api),
+) -> CustomerStatisticsResponse:
+    """Get customer statistics."""
+    stats = admin_customer_service.get_customer_stats(db=db, vendor_id=vendor_id)
+    return CustomerStatisticsResponse(**stats)
+
+
+# ============================================================================
+# Get Single Customer
+# ============================================================================
+
+
+@admin_router.get("/{customer_id}", response_model=CustomerDetailResponse)
+def get_customer(
+    customer_id: int,
+    db: Session = Depends(get_db),
+    current_admin: UserContext = Depends(get_current_admin_api),
+) -> CustomerDetailResponse:
+    """Get customer details by ID."""
+    customer = admin_customer_service.get_customer(db=db, customer_id=customer_id)
+    return CustomerDetailResponse(**customer)
+
+
+# ============================================================================
+# Toggle Customer Status
+# ============================================================================
+
+
+@admin_router.patch("/{customer_id}/toggle-status", response_model=CustomerMessageResponse)
+def toggle_customer_status(
+    customer_id: int,
+    db: Session = Depends(get_db),
+    current_admin: UserContext = Depends(get_current_admin_api),
+) -> CustomerMessageResponse:
+    """Toggle customer active status."""
+    result = admin_customer_service.toggle_customer_status(
+        db=db,
+        customer_id=customer_id,
+        admin_email=current_admin.email,
+    )
+    db.commit()
+    return CustomerMessageResponse(message=result["message"])