Add Cloud Run runtime guard alerts

[Pigbibi]

Summary

• add a Runtime Guard workflow that checks Cloud Scheduler and Cloud Run logs without invoking trading routes
• send Telegram alerts directly for Cloud Scheduler, Cloud Run, or optional missed-run heartbeat issues
• document setup and heartbeat behavior in English and Chinese

Validation

• python -m py_compile scripts/cloud_run_runtime_guard.py
• local dry run with scheduler check disabled
• real read-only Cloud Logging smoke with Telegram disabled
• git diff --check

[chatgpt-codex-connector]

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: 202c18cb46

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

[chatgpt-codex-connector]

Handle failed Telegram sends before exiting cleanly

When Telegram credentials are missing or the POST fails, _send_telegram() returns False, but this call ignores that result. In environments using the supported RUNTIME_GUARD_FAIL_WORKFLOW_ON_ALERT=false input/variable, the guard exits 0 even though no Telegram alert was delivered, so Cloud Run/Scheduler failures can be completely unreported except in the workflow log; please make send failures affect the exit status or otherwise surface them reliably.

Useful? React with 👍 / 👎.