M1 step 6: Wi-Fi Tools from ordinary scans

- lib/wifi (host-tested): channel occupancy (neighbour spill, signal
  weighting, quietest of 1/6/11) and a signal tracker (history, lost
  detection, click interval)
- WifiService: scan results carry BSSID, channel and security; a scan
  can target one channel for quick tracker refreshes; endListScans()
  turns the radio back off when Wi-Fi is disabled
- Wi-Fi Tools App: networks nearby, channel occupancy bars, signal
  tracker with clicks (m to mute)
- M1 plan: Monitoring-mode views and captures deferred

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EhqxQ49eCju4CzKYNjZzwT

src/main.cpp

@@ -6,6 +6,7 @@
 #include "apps/irc_app.h"
 #include "apps/launcher_app.h"
 #include "apps/settings_app.h"
+#include "apps/wifi_tools_app.h"
 #include "apps/setup_app.h"
 #include "event_bus.h"
 #include "key_mapper.h"
@@ -115,6 +116,7 @@ void setup() {
     apps = new AppManager(launcher);
     launcher.setManager(*apps);
     apps->registerApp({"irc", "IRC", false, new IrcApp(*irc, *clockService, bus)});
+    apps->registerApp({"wifi-tools", "Wi-Fi Tools", false, new WifiToolsApp(*wifi)});
     apps->registerApp({"settings", "Settings", false,
                        new SettingsApp({settings, bus, *apps, *battery, *storageService, *clockService, *wifi, *savedNetworks})});
     apps->registerApp({"demo", "Widget demo", true, new DemoApp(bus)});