fix(email): add EMAIL_DISABLE_AUTO_REPLY env var guard

[phuongvm]

What does this PR do?

Add EMAIL_DISABLE_AUTO_REPLY environment variable to pause IMAP polling and block all SMTP send operations while still receiving and processing inbound emails. This prevents unsolicited auto-replies while keeping inbound email processing and cron triage functional.

Related Issue

Fixes #

Type of Change

• 🐛 Bug fix (non-breaking change that fixes an issue)

Changes Made

gateway/platforms/email.py (+37/-3 lines)

1. IMAP polling guard (start_platform): Skip poll_loop creation when EMAIL_DISABLE_AUTO_REPLY=1/true/yes, with INFO log explaining the pause.
2. SMTP send guards (3 methods):
   • _send_email(): Return disabled message ID, log WARNING with recipient and subject
   • _send_email_with_attachments(): Return disabled message ID, log WARNING
   • _send_email_with_file(): Return disabled message ID, log WARNING
3. All three send methods return a synthetic message ID format <hermes-disabled-{uuid}@{domain}> so callers don't crash.
4. Cron job triage (email_watch_hourly.py) is unaffected — inbound emails still processed.

How to Test

1. Set EMAIL_DISABLE_AUTO_REPLY=1 in environment or .env
2. Restart gateway: systemctl --user restart hermes-gateway
3. Verify in logs: [Email] Platform PAUSED — IMAP polling disabled by EMAIL_DISABLE_AUTO_REPLY
4. Send an email to the configured address — verify it's received and processed but no reply is sent
5. Unset the variable and restart — verify normal operation resumes

Checklist

Code

• I've read the Contributing Guide
• My commit messages follow Conventional Commits
• I searched for existing PRs to make sure this isn't a duplicate
• My PR contains only changes related to this fix/feature (no unrelated commits)
• I've run pytest tests/ -q and all tests pass
• I've tested on my platform: Ubuntu 24.04 (WSL2)

Documentation & Housekeeping

• I've considered cross-platform impact (Windows, macOS) per the compatibility guide — or N/A

Screenshots / Logs

[Email] Platform PAUSED — IMAP polling disabled by EMAIL_DISABLE_AUTO_REPLY. Cron job triage (email_watch_hourly.py) is unaffected.
[Email] AUTO-REPLY DISABLED — would have sent to user@example.com (subject: Test). Set EMAIL_DISABLE_AUTO_REPLY=0 to re-enable.

[alt-glitch]

Related: #5717 (EMAIL_SUPPRESS_OUTBOUND kill switch). Similar concept — #5717 blocks SMTP only, this PR also pauses IMAP polling. Consider consolidating.

[phuongvm]

Good catch on the relation to #5717. The key difference is scope:

• feat(gateway): add EMAIL_SUPPRESS_OUTBOUND kill switch for draft-only mailboxes #5717 (EMAIL_SUPPRESS_OUTBOUND): Blocks SMTP send only
• This PR (EMAIL_DISABLE_AUTO_REPLY): Blocks SMTP sends AND pauses IMAP polling, while keeping inbound email processing and cron triage functional

The use case here is preventing unsolicited auto-replies during debugging/testing windows — we want to stop all automated email activity (both sending and polling-triggered actions) while still receiving and triaging inbound mail.

Consolidation into a unified suppression mechanism makes sense as a follow-up, but I think this PR is valuable standalone since it addresses a different operational need. Happy to discuss merging approaches if maintainers prefer.

[teknium1]

Thanks for addressing the operator need to prevent unintended email replies. The member discussion linking #5717 was useful context.

This automated hermes-sweeper review is closing the PR as a configuration-direction mismatch:

• The proposed public mechanism, EMAIL_DISABLE_AUTO_REPLY, is a non-secret behavioral feature flag in .env. Repository policy requires behavioral settings and feature flags to live in config.yaml instead (AGENTS.md:102-107, AGENTS.md:620-623).
• The submitted change targets gateway/platforms/email.py, which was removed when email moved into the bundled platform plugin in 560010547. Current SMTP paths are in plugins/platforms/email/adapter.py, including the adapter sends (:921-1165) and standalone delivery (:1190-1230).

A focused follow-up using a platforms.email config setting, integrated with the email plugin and every current SMTP egress path, would be the supported direction.

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Closed as not-planned per standing maintainer policy (env-var-for-config). This is an automated hermes-sweeper review and a configuration-direction decision, not a judgment on the contribution’s quality.

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Closed as not-planned per standing maintainer policy (env-var-for-config). This is a design-direction decision, not a code-quality judgment — see the Contribution Rubric in AGENTS.md for what the project is looking for. If you believe this policy was misapplied to your change, comment here and a maintainer will take a look.