lint: enforce unawaited_futures, prefer_final_locals, etc.

lib/utils/json_utils.dart

@@ -3,8 +3,8 @@
 /// to handle Plex API responses where numeric fields may arrive as strings
 /// (XML-to-JSON conversion).
 int? flexibleInt(Object? v) => switch (v) {
-  num n => n.toInt(),
-  String s => int.tryParse(s),
+  final num n => n.toInt(),
+  final String s => int.tryParse(s),
   _ => null,
 };
 
@@ -12,16 +12,16 @@ int? flexibleInt(Object? v) => switch (v) {
 /// Returns `false` for `null` or unrecognised values.
 /// Handles Plex API responses where boolean fields may arrive as integers.
 bool flexibleBool(Object? v) => switch (v) {
-  bool b => b,
-  int n => n == 1,
-  String s => s == '1',
+  final bool b => b,
+  final int n => n == 1,
+  final String s => s == '1',
   _ => false,
 };
 
 /// Parse a value that may be [double], [num], or [String] to [double].
 double? flexibleDouble(Object? v) => switch (v) {
-  num n => n.toDouble(),
-  String s => double.tryParse(s),
+  final num n => n.toDouble(),
+  final String s => double.tryParse(s),
   _ => null,
 };
 
@@ -36,6 +36,6 @@ Object? readStringField(Map json, String key) => json[key]?.toString();
 /// Returns `null` when the value is `null`.
 List<dynamic>? flexibleList(Object? v) => switch (v) {
   null => null,
-  List l => l,
+  final List l => l,
   _ => <dynamic>[v],
 };

lib/utils/live_tv_player_navigation.dart

@@ -1,3 +1,5 @@
+import 'dart:async';
+
 import 'package:flutter/material.dart';
 
 import '../models/livetv_channel.dart';
@@ -43,5 +45,5 @@ Future<void> navigateToLiveTv(
     reverseTransitionDuration: Duration.zero,
   );
 
-  navigator.push<bool>(route);
+  unawaited(navigator.push<bool>(route));
 }