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/services/works-square-runtime.ts

@@ -4,8 +4,8 @@ import { clearWorksSquareAIGatewayCredential } from './works-square-ai-gateway';
 import { getProviderService } from './providers/provider-service';
 
 export type WorksSquareRuntimeContext = {
-  opencodeManager: {
-    stop(): Promise<unknown>;
+  codingProducts?: {
+    sleep(): Promise<unknown>;
   };
   imageWorkspace?: {
     closeEventSessions?(options?: {
@@ -31,7 +31,7 @@ async function runManagedWorksSquareRuntimeCleanup(
       accessToken,
       tolerateRemoteFailure,
     }))(),
-    (async () => await ctx.opencodeManager.stop())(),
+    (async () => await ctx.codingProducts?.sleep())(),
     (async () => {
       const deleted = await getProviderService().deleteAccountApiKey(
         NIANCODE_USER_MODEL_ACCOUNT_ID,