[codex] Add desktop reconnecting proxy troubleshooting

[toby-bridges]

Summary

• Add a user-facing Reconnecting troubleshooting section to the CodexGuide troubleshooting manual.
• Clarify the boundary between config.toml and ~/.codex/.env for Desktop/IDE environment variables.
• Link to OpenAI docs and the community fact-check guide for higher-fidelity follow-up.
• Add a short caution for macOS one-shot scripts: treat them as templates unless they back up .env, validate proxy protocol with curl -x, and avoid overwriting secrets.

Validation

• git diff --check
• corepack pnpm build rendered 58 pages successfully
• rg -n "C:\\Users\\john|Downloads|????\\+|Hermes agent|waytoagi|Feishu Document|lcnniolukk80" returned no matches

[vercel]

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