v1.7.1: GPS time sync, timezone picker, status bar clock

- GPS time sync via UBlox MIA-M10Q (38400 baud auto-detect)
- Custom zero-dependency NMEA parser with XOR checksum validation
- Only trust GPS time when satellites > 0 (no stale RTC cache)
- DST-aware timezone picker at first boot (21 cities, POSIX TZ strings)
- Timezone also configurable in Settings > GPS/Time
- GPS Time on by default, GPS Location off by default (opt-in)
- Status bar: clock (top-left), Ratspeak.org (center), battery (right)
- 12h time default (no AM/PM), configurable 24h in settings
- NVS persistence of GPS time for approximate timestamps across reboots
- Fix factory reset Enter key bleed-through (600ms input guard)
- Fix hardcoded UTC-5 NTP timezone (now uses DST-aware POSIX TZ)

src/ui/screens/LvSettingsScreen.cpp

@@ -3,6 +3,7 @@
 #include "ui/LvTheme.h"
 #include "config/Config.h"
 #include "config/UserConfig.h"
+#include "ui/screens/LvTimezoneScreen.h"  // For TIMEZONE_TABLE
 #include "storage/FlashStore.h"
 #include "storage/SDStore.h"
 #include "radio/SX1262.h"
@@ -382,10 +383,14 @@ void LvSettingsScreen::buildItems() {
         [](int v) { return v ? String("ON") : String("OFF"); }});
     idx++;
 #endif
-    _items.push_back({"UTC Offset", SettingType::INTEGER,
-        [&s]() { return (int)s.utcOffset; }, [&s](int v) { s.utcOffset = (int8_t)v; },
-        [](int v) { char buf[8]; snprintf(buf, sizeof(buf), "UTC%+d", v); return String(buf); },
-        -12, 14, 1});
+    _items.push_back({"Timezone", SettingType::INTEGER,
+        [&s]() { return (int)s.timezoneIdx; },
+        [&s](int v) { s.timezoneIdx = (uint8_t)v; s.timezoneSet = true; },
+        [](int v) {
+            if (v >= 0 && v < TIMEZONE_COUNT) return String(TIMEZONE_TABLE[v].label);
+            return String("Unknown");
+        },
+        0, TIMEZONE_COUNT - 1, 1});
     idx++;
     _items.push_back({"24h Time", SettingType::TOGGLE,
         [&s]() { return s.use24HourTime ? 1 : 0; },
@@ -394,9 +399,9 @@ void LvSettingsScreen::buildItems() {
     idx++;
     _categories.push_back({"GPS/Time", gpsStart, idx - gpsStart,
         [&s]() {
-            char buf[16];
-            snprintf(buf, sizeof(buf), "UTC%+d", s.utcOffset);
-            return String(buf);
+            if (s.timezoneIdx < TIMEZONE_COUNT)
+                return String(TIMEZONE_TABLE[s.timezoneIdx].label);
+            return String("Not set");
         }});
 
     // Audio
@@ -540,7 +545,7 @@ void LvSettingsScreen::buildItems() {
             if (_sd && _sd->isReady()) _sd->wipeRatputer();
             if (_flash) _flash->format();
             nvs_flash_erase();
-            delay(500);
+            delay(1500);  // Long enough for key state to clear before reboot
             ESP.restart();
         };
         _items.push_back(factoryReset);