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/composables/useApi.ts

@@ -2,16 +2,14 @@ import type { $Fetch } from "nitropack";
 
 /**
  * Base API client composable.
- * Wraps $fetch with the configured API base URL from runtime config.
- * Provides typed GET, POST, PUT, DELETE helpers.
+ * Uses server-side apiBase for SSR requests, public apiBase for client-side.
  */
 export function useApi() {
   const config = useRuntimeConfig();
-  const apiBase = config.public.apiBase;
+  // On server: config.apiBase (http://backend:8000)
+  // On client: config.public.apiBase (/api)
+  const apiBase = import.meta.server ? config.apiBase : config.public.apiBase;
 
-  /**
-   * Typed $fetch wrapper bound to API base URL.
-   */
   const client: $Fetch = $fetch.create({
     baseURL: apiBase,
     headers: {