Add companion radio stats, adaptive backoff, path hash width, and UI improvements

- Companion radio stats: poll and display noise floor, RSSI, SNR, airtime
  with dedicated ValueNotifier and ref-counted polling
- Adaptive RF-aware TX backoff based on radio conditions instead of fixed 5s
- Variable-width path hash support (1-3 bytes per hop)
- Air activity dot indicator in app bar with tap to open stats screen
- Jump to oldest unread setting for chat screens
- 1s send cooldown on DM and channel messages
- Link style: theme-aware orange, added EmailLinkifier
- New languages: Hungarian, Japanese, Korean
- Remove dead DeviceScreen and BatteryIndicatorChip
- Remove wakelock_plus dependency
- TX power fields now read as signed int8

lib/helpers/link_handler.dart

@@ -10,10 +10,7 @@ class LinkHandler {
     final orange = brightness == Brightness.dark
         ? const Color(0xFFFFB74D)
         : const Color(0xFFE65100);
-    return base.copyWith(
-      color: orange,
-      decoration: TextDecoration.underline,
-    );
+    return base.copyWith(color: orange, decoration: TextDecoration.underline);
   }
 
   /// Returns a [SelectableLinkify] on desktop or a [Linkify] on mobile.
@@ -23,8 +20,7 @@ class LinkHandler {
     required TextStyle style,
     TextStyle? linkStyle,
   }) {
-    final effectiveLinkStyle =
-        linkStyle ?? defaultLinkStyle(context, style);
+    final effectiveLinkStyle = linkStyle ?? defaultLinkStyle(context, style);
     const options = LinkifyOptions(humanize: false, defaultToHttps: false);
     const linkifiers = [UrlLinkifier(), EmailLinkifier()];
     void onOpen(LinkableElement link) => handleLinkTap(context, link.url);