fix: allow slower OpenCode startup on Linux ARM

OpenCode health polling restored a ten-second startup limit, causing Linux ARM systems and QEMU environments that became healthy just after that boundary to be reported unavailable. Managed local OpenCode now retains health-based readiness detection while allowing up to thirty seconds for startup.

Release note: 修复部分 Linux ARM 设备切换 OpenCode 时因启动超过 10 秒而误报超时的问题；健康检查现在最多等待 30 秒。

src/main/agent/opencode-runtime.ts

@@ -67,7 +67,7 @@ import {
 import { toOpenCodeSubagentEvent } from './opencode-subagent'
 import { promptWithUntrustedConversationHistory } from './runtime-conversation-history'
 
-const STARTUP_TIMEOUT_MS = 10_000
+const STARTUP_TIMEOUT_MS = 30_000
 const STARTUP_POLL_INTERVAL_MS = 100
 const STARTUP_PROBE_TIMEOUT_MS = 500
 const CONTROL_REQUEST_TIMEOUT_MS = 30_000
@@ -1079,7 +1079,7 @@ export class OpenCodeRuntime implements AgentRuntime {
           }
         }
         const timeout = setTimeout(() => {
-          fail('OpenCode Server 启动超时（10 秒）')
+          fail('OpenCode Server 启动超时（30 秒）')
         }, this.dependencies.startupTimeoutMs)
 
         if (!stdout || !stderr) {