docs + nit: busy_ack_enabled follow-ups

- Move the disabled-ack guard above the debounce so we don't stamp
  _busy_ack_ts[session_key] when no ack was actually sent. Harmless
  (never read when disabled) but cosmetically off.
- Document display.busy_ack_enabled in user-guide/messaging/index.md
  and HERMES_GATEWAY_BUSY_ACK_ENABLED in reference/environment-variables.md.
- Add JezzaHehn to scripts/release.py AUTHOR_MAP for contributor credit.

Follow-up to #17491 (Jezza Hehn).

website/docs/reference/environment-variables.md

@@ -406,6 +406,7 @@ Advanced per-platform knobs for throttling the outbound message batcher. Most us
 | `HERMES_RESTART_DRAIN_TIMEOUT` | Gateway: seconds to wait for active runs to drain on `/restart` before forcing the restart (default: `900`). |
 | `HERMES_GATEWAY_PLATFORM_CONNECT_TIMEOUT` | Per-platform connect timeout during gateway startup (seconds). |
 | `HERMES_GATEWAY_BUSY_INPUT_MODE` | Default gateway busy-input behavior: `queue`, `steer`, or `interrupt`. Can be overridden per chat with `/busy`. |
+| `HERMES_GATEWAY_BUSY_ACK_ENABLED` | Whether the gateway sends an acknowledgment message (⚡/⏳/⏩) when a user sends input while the agent is busy (default: `true`). Set to `false` to suppress these messages entirely — the input is still queued/steered/interrupts as normal, only the chat reply is silenced. Bridged from `display.busy_ack_enabled` in `config.yaml`. |
 | `HERMES_CRON_TIMEOUT` | Inactivity timeout for cron job agent runs in seconds (default: `600`). The agent can run indefinitely while actively calling tools or receiving stream tokens — this only triggers when idle. Set to `0` for unlimited. |
 | `HERMES_CRON_SCRIPT_TIMEOUT` | Timeout for pre-run scripts attached to cron jobs in seconds (default: `120`). Override for scripts that need longer execution (e.g., randomized delays for anti-bot timing). Also configurable via `cron.script_timeout_seconds` in `config.yaml`. |
 | `HERMES_CRON_MAX_PARALLEL` | Max cron jobs run in parallel per tick (default: `4`). |