fix(codex): preserve apps in managed remote startup

[danshapiro]

Summary

• preserve codex --remote, codex_apps, and Freshell MCP instead of disabling Apps
• pass the same Freshell MCP -c mcp_servers.freshell... config and FRESHELL_* environment into the managed codex app-server sidecar, which is the process that actually boots codex_apps
• preallocate Codex terminal IDs so the visible TUI, managed app-server, registry record, and Freshell MCP target all agree on one terminal identity
• keep Codex launch validation ahead of layout mutation for /api/tabs and /api/run
• retain the prior startup-probe/session-identity fixes and remove the temporary features.apps=false workaround

Root cause

• Freshell passed Freshell MCP config only to the visible codex --remote TUI process
• codex --remote did not forward that local config to the external codex app-server; traced thread/start showed config: null
• the TUI waited for MCP server readiness based on local expectations, while the app-server only booted its own servers, leaving the header stuck on Booting MCP server: codex_apps

Validation

• npm run test:server -- --run test/unit/server/coding-cli/codex-app-server/launch-planner.test.ts test/integration/server/codex-session-flow.test.ts
• npm run test:server -- --run test/server/agent-panes-write.test.ts test/server/agent-run.test.ts test/server/agent-tabs-write.test.ts test/server/ws-protocol.test.ts test/server/ws-terminal-create-reuse-running-codex.test.ts
• FRESHELL_TEST_SUMMARY='codex app-server no-loss startup fix before local main landing' npm test
• real local smoke with proxy tracing: managed app-server reports both freshell and codex_apps MCP readiness, and the Codex prompt appears without disabling Apps

[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Avoid unconditional flush for split agent-chat panes

When tabHasSinglePane is false, this passes undefined as currentTab into buildAgentChatPersistedIdentityUpdate, but that helper still treats the missing tab session as a mismatch and sets shouldFlush to true. In split tabs, any subsequent session updates can therefore keep dispatching flushPersistedLayoutNow() even when neither pane nor tab identity actually changed, causing unnecessary immediate persistence work and write churn.

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