fix: skip repeated OpenCode binary validation

OpenCode startup on Linux ARM could run a --version probe before launching the configured Runtime and recheck registered remote binary metadata. Execution now trusts the selected path and registered manifest identity after setup-time verification, so switching and cold launch avoid duplicate binary work.

Release note: 优化 Linux ARM 上切换 OpenCode 的启动速度；已安装或已登记的 Runtime 在执行时不再重复启动或检查二进制。

src/agent-daemon/runtime-bundle-verifier.test.ts

@@ -213,11 +213,8 @@ describe('Remote Runtime bundle verifier', () => {
         Buffer.from('changed')
       ])
     )
-    await expect(capabilities()).resolves.toEqual([])
-    expect(reportError).toHaveBeenCalledWith(
-      'Verified Runtime unavailable: opencode',
-      expect.any(Error)
-    )
+    await expect(capabilities()).resolves.toHaveLength(1)
+    expect(reportError).not.toHaveBeenCalled()
   })
 
   it('adopts signed published metadata without rehashing unrelated payload', async () => {