feat: add frontend API clients for device types and network diagrams

Adds deviceTypesApi (list, create, update, remove) and networkDiagramsApi
(list, get, create, update, archive, duplicate, exportJson, importJson,
aiGenerate, listClients) following the existing apiClient module pattern.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/api/index.ts

@@ -35,3 +35,5 @@ export { betaFeedbackApi } from './betaFeedback'
 export { branchesApi } from './branches'
 export { handoffsApi } from './handoffs'
 export { resolutionsApi } from './resolutions'
+export { deviceTypesApi } from './deviceTypes'
+export { networkDiagramsApi } from './networkDiagrams'