feat: Segment article text for improved playback

Splits article content into smaller audio segments. This allows for more granular control over playback, faster processing, and improved user experience by enabling auto-scrolling to the currently read segment.

Updates `types.ts` to include `AudioSegment` interface and modify `Article` to hold `segments`, `currentSegmentIndex`, and `audioUrl` per segment.

Introduces `segmentText` utility in `services/textUtils.ts` for robust text segmentation logic.

Modifies `App.tsx` to utilize the new segmentation approach for fetching and processing audio.

Enhances `components/ReaderView.tsx` to display and auto-scroll through segmented text, highlighting the current segment during playback.

types.ts

@@ -1,3 +1,4 @@
+
 export enum VoiceName {
   Puck = 'Puck',
   Charon = 'Charon',
@@ -17,12 +18,23 @@ export enum PlaybackStatus {
   COMPLETED = 'COMPLETED'
 }
 
+export interface AudioSegment {
+  id: string;
+  text: string;
+  audioUrl?: string; // Blob URL for this specific segment
+  isLoading: boolean;
+  hasError: boolean;
+}
+
 export interface Article {
   id: string;
   url: string;
   title: string;
+  // We keep the full text for display/reference
   text: string;
-  audioUrl?: string; // Blob URL for the WAV file
+  // We split content into segments for faster playback
+  segments: AudioSegment[];
+  currentSegmentIndex: number; 
   status: PlaybackStatus;
   errorMessage?: string;
 }
@@ -32,4 +44,4 @@ export interface PlayerState {
   playbackRate: number;
   currentArticleId: string | null;
   selectedVoice: VoiceName;
-}
+}