fix(gateway): prevent background process notifications from triggering false pairing requests

[xingkongliang]

Summary

• When a background process with notify_on_complete=True finishes, the gateway injects a synthetic MessageEvent to notify the session. This event was constructed without user_id, causing _is_user_authorized() to reject it and trigger the DM pairing flow — sending "Hi~ I don't recognize you yet!" with a pairing code to the bot owner's own chat.
• Added an internal flag to MessageEvent that bypasses authorization for system-generated synthetic events. Only the process watcher sets this flag.
• Includes 4 regression tests covering the fix and verifying normal pairing still works for real unauthorized users.

Changes

• gateway/platforms/base.py: Add internal: bool = False field to MessageEvent
• gateway/run.py: Skip _is_user_authorized() when event.internal is True; set internal=True on process watcher synthetic events
• tests/gateway/test_internal_event_bypass_pairing.py: 4 new tests

Test plan

• test_notify_on_complete_sets_internal_flag — synthetic completion event has internal=True
• test_internal_event_bypasses_authorization — _is_user_authorized is never called for internal events
• test_internal_event_does_not_trigger_pairing — no pairing code generated for internal events
• test_non_internal_event_without_user_triggers_pairing — normal unauthorized DM still triggers pairing (regression guard)
• All 14 existing test_background_process_notifications.py tests pass

🤖 Generated with Claude Code

[blasai1739217-cmyk]

Friendly bump on this PR in case it fell through the cracks \u2014 would love a review when someone has a minute. Thanks!

[nocoo]

We're also hitting this bug. When running Claude Code CLI or Codex CLI via terminal(background=true, notify_on_complete=true) from a Discord DM session, each process completion triggers a false pairing request ("Hi~ I don't recognize you yet!").

Reproduction: any notify_on_complete=true background process in a gateway DM session.

Root cause confirmed: the synthetic SessionSource at L6129 of gateway/run.py is missing user_id/user_name, so it fails _is_user_authorized() and defaults to chat_type="dm", which triggers pairing_store.generate_code().

Would love to see this merged — the internal flag approach looks clean. 👍

[jeanfbrito]

Me too, I was going to do the PR but found this here. This feature is awaited for me, and this fix is needed. I will be running from this PR until this gets merged.
Thank you @xingkongliang

[teknium1]

Merged via PR #6434. Your commit was cherry-picked onto current main with your authorship preserved in git log. Added a small follow-up fix for test env var isolation. Thanks @xingkongliang!