Unified package/total speed calculation, confirm dialog for context menu delete, show progress bar when collapsed

- Track packageId in speed events so package speed uses same 3-second
  window as global speed (fixes mismatch between package and status bar)
- Add packageSpeedBps to UiSnapshot, computed from speed events
- Context menu delete actions now respect confirmDeleteSelection setting
- Progress bar visible even when package is collapsed

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

src/shared/types.ts

@@ -161,6 +161,7 @@ export interface UiSnapshot {
   canPause: boolean;
   clipboardActive: boolean;
   reconnectSeconds: number;
+  packageSpeedBps: Record<string, number>;
 }
 
 export interface AddLinksPayload {