Enhance contribution guidelines and improve FloatingGenerateBox component

- Updated CONTRIBUTING.md to include instructions for building with a local Qwen3-TTS development version, facilitating easier testing and development.
- Refactored FloatingGenerateBox component to streamline the rendering of text and instruct fields, improving code readability and maintainability.
- Added functionality to handle auto-resizing of text areas based on content changes, enhancing user experience.
- Improved event handling for keyboard interactions in StoryTrackEditor, allowing for play/pause functionality with the spacebar.
- Introduced a MiniSamplePlayer component in SampleList for better audio playback control, including play, pause, and seek features.
- Implemented sample update functionality in the backend, allowing users to edit reference text for audio samples, with appropriate error handling and user feedback.

app/src/lib/api/client.ts

@@ -120,6 +120,16 @@ class ApiClient {
     });
   }
 
+  async updateProfileSample(
+    sampleId: string,
+    referenceText: string,
+  ): Promise<ProfileSampleResponse> {
+    return this.request<ProfileSampleResponse>(`/profiles/samples/${sampleId}`, {
+      method: 'PUT',
+      body: JSON.stringify({ reference_text: referenceText }),
+    });
+  }
+
   async exportProfile(profileId: string): Promise<Blob> {
     const url = `${this.getBaseUrl()}/profiles/${profileId}/export`;
     const response = await fetch(url);