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/module-navigation.test.tsx

@@ -4,7 +4,7 @@ import { MemoryRouter, Route, Routes, useLocation } from 'react-router-dom';
 import { ModuleSwitcher } from '@/components/layout/ModuleSwitcher';
 import { ModuleSelection } from '@/pages/ModuleSelection';
 import { useAuthStore } from '@/stores/auth';
-import { useOpencodeStore } from '@/stores/opencode';
+import { codingWorkspaceStore } from '@/stores/coding-workspace';
 import { useUserProfileStore } from '@/stores/user-profile';
 
 const { hostApiFetchMock } = vi.hoisted(() => ({
@@ -34,7 +34,7 @@ describe('AI module navigation', () => {
       legacyRefreshToken: null,
       user: { username: 'zhangsan@example.com', userId: 'user-1', tenantId: null, deptId: null, authorities: [] },
     });
-    useOpencodeStore.setState({ activeProject: null });
+    codingWorkspaceStore.setState({ activeProject: null });
     useUserProfileStore.setState({ profilesByUserId: {}, syncStatesByUserId: {} });
     hostApiFetchMock.mockResolvedValue({
       success: true,
@@ -160,7 +160,7 @@ describe('AI module navigation', () => {
     );
 
     fireEvent.click(screen.getByTestId('ai-module-option-programming'));
-    expect(await screen.findByTestId('location-path')).toHaveTextContent('/opencode-chat');
+    expect(await screen.findByTestId('location-path')).toHaveTextContent('/chat');
   });
 
   it('keeps the chooser public and sends signed-out users to login when they choose a module', async () => {
@@ -289,7 +289,7 @@ describe('AI module navigation', () => {
 
   it('keeps breathing room around the compact module switcher trigger', () => {
     render(
-      <MemoryRouter initialEntries={['/opencode-chat']}>
+      <MemoryRouter initialEntries={['/chat']}>
         <ModuleSwitcher sidebarCollapsed={false} compact />
       </MemoryRouter>,
     );