Wi-Fi Tools: scan logging to CSV, plus sort and filter

- lib/wifi (host-tested): scan_log (CSV field quoting, header/row, a
  once-per-interval throttle) and network_list_view (sort by signal /
  channel / name, filter open-only / hide-hidden / strong-only)
- ScanEntry moved to lib/wifi so both are testable on the PC
- Wi-Fi Tools networks view: s sort, o/h/w filters, l toggles logging
  to /wifi/scans/<date>.csv (header + one row per AP per logged scan,
  throttled 30 s, needs the clock for timestamps); foreground-only
- Wi-Fi scan logs replace probe-request logs as a clean-up category
- Serial: cat <path>, and key <char> injects a character

Verified on the device: CSV written with header, timestamps, BSSID,
channel, RSSI, security and SSID; hidden networks marked.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EhqxQ49eCju4CzKYNjZzwT

src/services/wifi_service.h

@@ -4,6 +4,7 @@
 
 #include "event_bus.h"
 #include "saved_networks.h"
+#include "scan_entry.h"
 #include "service.h"
 #include "services/clock_service.h"
 #include "settings.h"
@@ -11,15 +12,6 @@
 
 namespace roro {
 
-struct ScanEntry {
-    std::string ssid;  // empty for a hidden network
-    std::string bssid;
-    int channel;
-    int rssi;
-    bool open;
-    std::string security;  // "open", "WPA2", "WPA3"...
-};
-
 // Owns the Wi-Fi radio: carries out the WifiController's decisions with the ESP32 Wi-Fi stack,
 // syncs the clock over NTP once Connected, and runs scans for the Settings network list.
 class WifiService : public Service {