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/user-sync-contract.test.ts

@@ -80,7 +80,7 @@ describe('user sync contract sanitizers', () => {
       description: 'Reusable partner',
       prompt: 'Reusable prompt',
       skillIds: ['pm-project-plan'],
-      filePath: 'D:/repo/.opencode/agent/makelore-pm-test.md',
+      filePath: 'D:/repo/local/agent/makelore-pm-test.md',
       projectRuntimeConfigsByProjectId: { prj_1: { filePath: 'D:/repo/file.md' } },
       createdAt: '2026-07-04T00:00:00.000Z',
       updatedAt: '2026-07-04T00:00:00.000Z',
@@ -123,7 +123,7 @@ describe('user sync contract sanitizers', () => {
         display_name: 'PM',
         template_role_id: 'custom',
         skill_ids: ['pm-project-plan'],
-        file_path: 'D:/repo/.opencode/agent/makelore-pm-test.md',
+        file_path: 'D:/repo/local/agent/makelore-pm-test.md',
         created_at: '2026-07-04T00:00:00.000Z',
         updated_at: '2026-07-04T00:00:00.000Z',
       }],