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.

tests/unit/main-layout-sidebar-peek.test.tsx

@@ -2,7 +2,7 @@ import { act, fireEvent, render, screen } from '@testing-library/react';
 import { MemoryRouter, Route, Routes } from 'react-router-dom';
 import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
 import { MainLayout } from '@/components/layout/MainLayout';
-import { useOpencodeStore } from '@/stores/opencode';
+import { codingWorkspaceStore } from '@/stores/coding-workspace';
 import { useSettingsStore } from '@/stores/settings';
 
 type PeekProps = {
@@ -42,7 +42,7 @@ vi.mock('@/components/layout/Sidebar', () => ({
 
 function renderLayout() {
   render(
-    <MemoryRouter initialEntries={['/opencode-chat']}>
+    <MemoryRouter initialEntries={['/chat']}>
       <Routes>
         <Route element={<MainLayout />}>
           <Route path="*" element={null} />
@@ -56,7 +56,7 @@ describe('MainLayout sidebar hover preview', () => {
   beforeEach(() => {
     vi.useFakeTimers();
     useSettingsStore.setState({ sidebarCollapsed: true });
-    useOpencodeStore.setState({ activeProject: null });
+    codingWorkspaceStore.setState({ activeProject: null });
   });
 
   afterEach(() => {