feat: add synopsis generation endpoint and frontend integration

qwen3-tts-frontend/src/lib/api/audiobook.ts

@@ -1,5 +1,15 @@
 import apiClient from '@/lib/api'
 
+export interface SynopsisGenerationRequest {
+  genre: string
+  subgenre?: string
+  protagonist_type?: string
+  tone?: string
+  conflict_scale?: string
+  num_characters?: number
+  num_chapters?: number
+}
+
 export interface ScriptGenerationRequest {
   title: string
   genre: string
@@ -69,6 +79,11 @@ export interface LLMConfig {
 }
 
 export const audiobookApi = {
+  generateSynopsis: async (data: SynopsisGenerationRequest): Promise<string> => {
+    const response = await apiClient.post<{ synopsis: string }>('/audiobook/projects/generate-synopsis', data)
+    return response.data.synopsis
+  },
+
   createAIScript: async (data: ScriptGenerationRequest): Promise<AudiobookProject> => {
     const response = await apiClient.post<AudiobookProject>('/audiobook/projects/generate-script', data)
     return response.data