fix(homeboy): give the daemon the bridge session sender so cook notifications deliver

[chubes4]

Summary

homeboy-daemon.service drains Homeboy's notification outbox, but it had neither a session sender nor Discord REST credentials. Every cook notification failed with Configure exactly one auth mode, and 366 are sitting in the dead-letter outbox on extrachill.com. Closes #715.

Changes

• bridges/_dispatch.sh: documents the optional bridge_session_sender_command hook.
• bridges/roadie.sh: Roadie implements bridge_session_sender_command as <roadie_bin> send. It also adds bridge_session_sender_env, which provides ROADIE_SERVICE_TOKEN_FILE and ROADIE_LOCK_PORT when it is set.
• services/homeboy-daemon.sh: the unit renders HOMEBOY_SESSION_SEND_COMMAND plus the sender env only when a bridge provides the hook, and adds the sender's directory to PATH. Reconcile restarts the daemon on a changed unit only when it is idle; otherwise it warns. The file names no bridge, and the gate greps for that.
• tests/homeboy-daemon-service.sh: covers rendering with the Roadie bridge (sender, token file, PATH) and without any bridge (no sender).

Evidence

I dry-ran the Discord transport with the daemon's exact environment:

• as-is: failed: Configure exactly one auth mode
• with HOMEBOY_SESSION_SEND_COMMAND=".../roadie send": {"status":"dry_run","delivery":{"mode":"session","destination":"session_thread"}}

Tests

tests/homeboy-daemon-service.sh, tests/bridge-render.sh and tests/bridge-service-adapters.sh pass, and services/homeboy-daemon.sh contains no roadie literal.

AI assistance

• AI assistance: Yes
• Tool(s): Homeboy cook (OpenCode, anthropic/claude-sonnet-5); the diagnosis, review, local gate run and PR were done by Extra Chill Bot via Roadie.
• Used for: Implementation and tests.