Fix freshopencode first-send reload loss

[danshapiro]

Summary

• persist freshopencode pending local echo in pane state so a refresh keeps the submitted prompt visible
• mark OpenCode fresh-agent panes running immediately on first send so the bouncer starts before session materialization finishes
• add opencode serve request timeouts and idle recovery for failed first-send materialization

Verification

• npm run test:e2e:chromium -- freshopencode-first-send-reload-repro.spec.ts --reporter=line
• npm run test:vitest -- --config vitest.server.config.ts test/unit/server/fresh-agent/opencode-serve-adapter.test.ts test/unit/server/fresh-agent/opencode-serve-manager.test.ts --run
• npm run test:vitest -- test/unit/client/components/fresh-agent/FreshAgentView.test.tsx --run
• FRESHELL_TEST_SUMMARY="freshopencode first-send reload final check" npm run check