feat: remove legacy OpenCode runtime

Cut product flows over to Coding/Pi and retain only the migration-owned v1 boundary. Promote supported native optional packages because electron-builder omitted pnpm transitive optional closure from the packaged ASAR.

electron/api/coding-product-services.ts

@@ -40,6 +40,7 @@ export interface CodingProductComposition {
   conversations: CodingConversationService;
   runtime: CodingConversationRuntime;
   host: CodingProductHost;
+  sleep(): Promise<void>;
   shutdown(): Promise<void>;
 }