Step 3: Add admin API endpoints for pricing configuration

- Add PricingConfigResponse and PricingConfigUpdate schemas
- Create PricingService with validation logic
- Add GET and PUT endpoints in routes/pricing.py
- Add MANAGE_PRICING permission to admin role
- Register pricing router in main.py
- Add comprehensive API tests for permissions and validation

backend/main.py

@@ -16,6 +16,7 @@ from routes import availability as availability_routes
 from routes import exchange as exchange_routes
 from routes import invites as invites_routes
 from routes import meta as meta_routes
+from routes import pricing as pricing_routes
 from routes import profile as profile_routes
 from routes import test as test_routes
 from shared_constants import PRICE_REFRESH_SECONDS
@@ -91,6 +92,7 @@ app.include_router(auth_routes.router)
 app.include_router(audit_routes.router)
 app.include_router(profile_routes.router)
 app.include_router(availability_routes.router)
+app.include_router(pricing_routes.router)
 app.include_router(meta_routes.router)
 app.include_router(test_routes.router)