feat: implement audio file splitting functionality

- Added `splitFile` method to `LibraryStore` for splitting audio files into segments.
- Introduced `SplitSegmentRequest` and `SegmentMetadataInput` interfaces in models for segment metadata handling.
- Created `EditModePanel` component for editing segments, including waveform visualization and metadata assignment.
- Developed `WaveformEditorCanvas` for interactive waveform editing, supporting segment creation and resizing.
- Enhanced metadata handling in IPC with new fields for author and copyright.
- Updated styles for new components and improved UI interactions.

src/shared/ipc.ts

@@ -45,7 +45,7 @@ export interface RendererApi {
   /** Moves a file to another subdirectory under the library root. */
   moveFile(fileId: number, targetRelativeDirectory: string): Promise<import('./models').AudioFileSummary>;
   /** Automatically organizes a file based on its categories. */
-  organizeFile(fileId: number, metadata: { customName?: string | null; author?: string | null; rating?: number }): Promise<import('./models').AudioFileSummary>;
+  organizeFile(fileId: number, metadata: { customName?: string; author?: string; copyright?: string; rating?: number }): Promise<import('./models').AudioFileSummary>;
   /** Updates the custom name for a file. */
   updateCustomName(fileId: number, customName: string | null): Promise<import('./models').AudioFileSummary>;
   /** Opens the file's containing folder in the system file explorer. */
@@ -63,11 +63,11 @@ export interface RendererApi {
   /** Runs fuzzy search returning ranked results. */
   search(query: string): Promise<import('./models').AudioFileSummary[]>;
   /** Reads embedded metadata from a WAV file. */
-  readFileMetadata(fileId: number): Promise<{ author?: string; title?: string; rating?: number }>;
+  readFileMetadata(fileId: number): Promise<{ author?: string; copyright?: string; title?: string; rating?: number }>;
   /** Lists distinct metadata values gathered from the library for quick suggestions. */
-  listMetadataSuggestions(): Promise<{ authors: string[] }>;
-  /** Updates metadata (author, rating) without organizing the file. */
-  updateFileMetadata(fileId: number, metadata: { author?: string | null; rating?: number }): Promise<void>;
+  listMetadataSuggestions(): Promise<{ authors: string[]; copyrights: string[] }>;
+  /** Updates metadata (author, copyright, rating) without organizing the file. */
+  updateFileMetadata(fileId: number, metadata: { author?: string; copyright?: string; rating?: number }): Promise<void>;
   /** Listens for menu actions from the main process. Returns a cleanup function. */
   onMenuAction(channel: string, callback: () => void): () => void;
 }

src/shared/models.ts

@@ -107,3 +107,33 @@ export interface AudioBufferPayload {
   /** MIME type for the audio data. */
   mimeType: string;
 }
+
+/**
+ * Optional metadata overrides applied while creating split segments.
+ */
+export interface SegmentMetadataInput {
+  /** Overrides the custom name embedded into the segment (null clears it). */
+  customName?: string | null;
+  /** Overrides the author/creator metadata. */
+  author?: string | null;
+  /** Overrides the rating metadata (1-5). */
+  rating?: number;
+  /** Overrides the applied free-form tags. */
+  tags?: string[];
+  /** Overrides the applied UCS categories. */
+  categories?: string[];
+}
+
+/**
+ * Describes a region that should be extracted as a new audio segment.
+ */
+export interface SplitSegmentRequest {
+  /** Inclusive start offset in milliseconds. */
+  startMs: number;
+  /** Exclusive end offset in milliseconds. */
+  endMs: number;
+  /** Optional display label used for segment naming. */
+  label?: string;
+  /** Metadata overrides to apply to the generated file. */
+  metadata?: SegmentMetadataInput;
+}