Document the desktop tray applet and check --json

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

docs/COMMAND_REFERENCE.md

@@ -35,11 +35,13 @@ Expected use: systemd, not an interactive shell.
 
 ```bash
 enodia-sentinel check
+enodia-sentinel check --json
 ```
 
 Runs the enabled detector set once and prints alerts. This forces the SUID scan
 and arms baseline-gated detectors immediately, so it is useful for health checks
-and debugging.
+and debugging. `--json` emits the alerts as a JSON array of alert dicts
+(severity-ordered) instead of text, for scripts and the tray applet.
 
 Exit code:
 
@@ -381,6 +383,20 @@ text/status contrast pairs are covered by the web test suite.
 
 Expected use: `enodia-sentinel-web.service`.
 
+### `enodia-sentinel-tray`
+
+```bash
+enodia-sentinel-tray
+```
+
+Launches the optional desktop system-tray applet (no subcommands). It is a GUI
+frontend over the commands above: the menu opens the dashboard (starting
+`enodia-sentinel-web.service` if needed), starts/stops/restarts
+`enodia-sentinel.service` via `systemctl`, shows daemon status and alert counts
+from `status --json`, and runs `check --json` on demand with the result shown
+as a desktop notification. Requires the `[tray]` extra (`pystray`, `Pillow`);
+the core agent stays dependency-free without it.
+
 ### `triage`
 
 ```bash

docs/OPERATIONS.md

@@ -77,6 +77,12 @@ The HTTPS dashboard shows the same posture findings under the Posture tab and
 summarizes FIM/package anchors plus heartbeat freshness under the Integrity tab
 for quick remote review.
 
+On desktop hosts the optional tray applet (`enodia-sentinel-tray`, `[tray]`
+extra) wraps the same workflow: it drives the same `systemctl` units operators
+use directly, so daemon start/stop/restart prompts for polkit authorization as
+usual. The applet is purely a convenience frontend — it is not required for the
+daemon to run and adds nothing to the core agent.
+
 ## Alert Workflow
 
 When Sentinel fires:

docs/PACKAGING.md

@@ -103,6 +103,17 @@ Notes:
 - Validate package verification behavior on the target distro before enabling
   signed-package mismatch alerting.
 
+## Desktop Tray Applet (optional)
+
+The `[tray]` optional extra (`pip install 'enodia-sentinel[tray]'`) pulls in
+`pystray` and `Pillow` and provides the `enodia-sentinel-tray` console script.
+The extra is never required by the daemon; core runtime dependencies stay
+empty.
+
+`packaging/enodia-sentinel-tray.desktop` is an opt-in autostart entry. It is
+not installed to a system autostart path by default — desktop users copy it to
+`~/.config/autostart/` themselves.
+
 ## Package Hardening Checklist
 
 - Package version matches `pyproject.toml` and `enodia_sentinel.__version__`.