feat(T04): Rentman integration – equipment sync, API endpoints, frontend updates

- Update equipment model with Rentman-compatible fields
- Add/Update equipment router endpoints for sync operations
- Enhance rentman_service with full API client logic
- Improve sync_service for bidirectional equipment sync
- Update docker-compose with Rentman env vars
- Update frontend useApi composable and nuxt config
- Update mietkatalog pages with Rentman-integrated data display
- Add images/ to .gitignore (binary assets, 36MB)

frontend/nuxt.config.ts

@@ -51,9 +51,11 @@ export default defineNuxtConfig({
     },
   },
   runtimeConfig: {
-    apiBase: process.env.API_BASE_URL || "http://localhost:8000",
+    // Server-only: used by SSR to call backend in Docker network
+    apiBase: process.env.API_BASE_URL || "http://backend:8000",
     public: {
-      apiBase: process.env.API_BASE_URL || "http://localhost:8000",
+      // Client-side: relative URL goes through Nuxt server proxy
+      apiBase: "/api",
     },
   },
   routeRules: {
@@ -73,5 +75,10 @@ export default defineNuxtConfig({
   },
   nitro: {
     compressPublicAssets: true,
+    routeRules: {
+      "/api/**": {
+        proxy: "http://backend:8000/api/**",
+      },
+    },
   },
 });