Add configurable battery chemistry for repeaters

- Add per-repeater battery chemistry setting (NMC, LiFePO4, LiPo)
- Create shared battery_utils.dart for voltage-to-percentage calculation
- Support optional firmware-reported chemistry (protocol extension at byte 60)
- Show lock icon when chemistry is firmware-reported, dropdown when user-configurable
- Add l10n string for "Battery Type" label

Addresses #116

lib/l10n/app_en.arb

@@ -806,6 +806,7 @@
   },
   "repeater_systemInformation": "System Information",
   "repeater_battery": "Battery",
+  "repeater_batteryChemistry": "Battery Type",
   "repeater_clockAtLogin": "Clock (at login)",
   "repeater_uptime": "Uptime",
   "repeater_queueLength": "Queue Length",

lib/l10n/app_localizations.dart

@@ -3081,6 +3081,12 @@ abstract class AppLocalizations {
   /// **'Battery'**
   String get repeater_battery;
 
+  /// No description provided for @repeater_batteryChemistry.
+  ///
+  /// In en, this message translates to:
+  /// **'Battery Type'**
+  String get repeater_batteryChemistry;
+
   /// No description provided for @repeater_clockAtLogin.
   ///
   /// In en, this message translates to:

lib/l10n/app_localizations_bg.dart

@@ -1705,6 +1705,9 @@ class AppLocalizationsBg extends AppLocalizations {
   @override
   String get repeater_battery => 'Батерия';
 
+  @override
+  String get repeater_batteryChemistry => 'Battery Type';
+
   @override
   String get repeater_clockAtLogin => 'Часовник (при влизане)';
 

lib/l10n/app_localizations_de.dart

@@ -1702,6 +1702,9 @@ class AppLocalizationsDe extends AppLocalizations {
   @override
   String get repeater_battery => 'Akku';
 
+  @override
+  String get repeater_batteryChemistry => 'Battery Type';
+
   @override
   String get repeater_clockAtLogin => 'Uhr (bei Anmeldung)';
 

lib/l10n/app_localizations_en.dart

@@ -1675,6 +1675,9 @@ class AppLocalizationsEn extends AppLocalizations {
   @override
   String get repeater_battery => 'Battery';
 
+  @override
+  String get repeater_batteryChemistry => 'Battery Type';
+
   @override
   String get repeater_clockAtLogin => 'Clock (at login)';
 

lib/l10n/app_localizations_es.dart

@@ -1699,6 +1699,9 @@ class AppLocalizationsEs extends AppLocalizations {
   @override
   String get repeater_battery => 'Batería';
 
+  @override
+  String get repeater_batteryChemistry => 'Battery Type';
+
   @override
   String get repeater_clockAtLogin => 'Reloj (al inicio de sesión)';
 

lib/l10n/app_localizations_fr.dart

@@ -1710,6 +1710,9 @@ class AppLocalizationsFr extends AppLocalizations {
   @override
   String get repeater_battery => 'Batterie';
 
+  @override
+  String get repeater_batteryChemistry => 'Battery Type';
+
   @override
   String get repeater_clockAtLogin => 'Horloge (au démarrage)';
 

lib/l10n/app_localizations_it.dart

@@ -1699,6 +1699,9 @@ class AppLocalizationsIt extends AppLocalizations {
   @override
   String get repeater_battery => 'Batteria';
 
+  @override
+  String get repeater_batteryChemistry => 'Battery Type';
+
   @override
   String get repeater_clockAtLogin => 'Orologio (all\'accesso)';
 

lib/l10n/app_localizations_nl.dart

@@ -1693,6 +1693,9 @@ class AppLocalizationsNl extends AppLocalizations {
   @override
   String get repeater_battery => 'Batterij';
 
+  @override
+  String get repeater_batteryChemistry => 'Battery Type';
+
   @override
   String get repeater_clockAtLogin => 'Tijd (bij aanmelden)';
 

lib/l10n/app_localizations_pl.dart

@@ -1703,6 +1703,9 @@ class AppLocalizationsPl extends AppLocalizations {
   @override
   String get repeater_battery => 'Bateria';
 
+  @override
+  String get repeater_batteryChemistry => 'Battery Type';
+
   @override
   String get repeater_clockAtLogin => 'Godzina (przy logowaniu)';
 

lib/l10n/app_localizations_pt.dart

@@ -1700,6 +1700,9 @@ class AppLocalizationsPt extends AppLocalizations {
   @override
   String get repeater_battery => 'Bateria';
 
+  @override
+  String get repeater_batteryChemistry => 'Battery Type';
+
   @override
   String get repeater_clockAtLogin => 'Relógio (no login)';
 

lib/l10n/app_localizations_ru.dart

@@ -1702,6 +1702,9 @@ class AppLocalizationsRu extends AppLocalizations {
   @override
   String get repeater_battery => 'Батарея';
 
+  @override
+  String get repeater_batteryChemistry => 'Battery Type';
+
   @override
   String get repeater_clockAtLogin => 'Время (при входе)';
 

lib/l10n/app_localizations_sk.dart

@@ -1695,6 +1695,9 @@ class AppLocalizationsSk extends AppLocalizations {
   @override
   String get repeater_battery => 'Batéria';
 
+  @override
+  String get repeater_batteryChemistry => 'Battery Type';
+
   @override
   String get repeater_clockAtLogin => 'Čas (při přihlášení)';
 

lib/l10n/app_localizations_sl.dart

@@ -1694,6 +1694,9 @@ class AppLocalizationsSl extends AppLocalizations {
   @override
   String get repeater_battery => 'Baterija';
 
+  @override
+  String get repeater_batteryChemistry => 'Battery Type';
+
   @override
   String get repeater_clockAtLogin => 'Ure (pri prijavi)';
 

lib/l10n/app_localizations_sv.dart

@@ -1684,6 +1684,9 @@ class AppLocalizationsSv extends AppLocalizations {
   @override
   String get repeater_battery => 'Batteri';
 
+  @override
+  String get repeater_batteryChemistry => 'Battery Type';
+
   @override
   String get repeater_clockAtLogin => 'Klocka (vid inloggning)';
 

lib/l10n/app_localizations_uk.dart

@@ -1703,6 +1703,9 @@ class AppLocalizationsUk extends AppLocalizations {
   @override
   String get repeater_battery => 'Батарея';
 
+  @override
+  String get repeater_batteryChemistry => 'Battery Type';
+
   @override
   String get repeater_clockAtLogin => 'Годинник (при вході)';
 

lib/l10n/app_localizations_zh.dart

@@ -1623,6 +1623,9 @@ class AppLocalizationsZh extends AppLocalizations {
   @override
   String get repeater_battery => '电池';
 
+  @override
+  String get repeater_batteryChemistry => 'Battery Type';
+
   @override
   String get repeater_clockAtLogin => '登录时的时间';
 

lib/models/app_settings.dart

@@ -21,6 +21,7 @@ class AppSettings {
   final String? languageOverride; // null = system default
   final bool appDebugLogEnabled;
   final Map<String, String> batteryChemistryByDeviceId;
+  final Map<String, String> repeaterBatteryChemistryByPublicKey;
 
   AppSettings({
     this.clearPathOnMaxRetry = false,
@@ -43,7 +44,10 @@ class AppSettings {
     this.languageOverride,
     this.appDebugLogEnabled = false,
     Map<String, String>? batteryChemistryByDeviceId,
-  }) : batteryChemistryByDeviceId = batteryChemistryByDeviceId ?? {};
+    Map<String, String>? repeaterBatteryChemistryByPublicKey,
+  })  : batteryChemistryByDeviceId = batteryChemistryByDeviceId ?? {},
+        repeaterBatteryChemistryByPublicKey =
+            repeaterBatteryChemistryByPublicKey ?? {};
 
   Map<String, dynamic> toJson() {
     return {
@@ -67,6 +71,8 @@ class AppSettings {
       'language_override': languageOverride,
       'app_debug_log_enabled': appDebugLogEnabled,
       'battery_chemistry_by_device_id': batteryChemistryByDeviceId,
+      'repeater_battery_chemistry_by_public_key':
+          repeaterBatteryChemistryByPublicKey,
     };
   }
 
@@ -101,6 +107,11 @@ class AppSettings {
             (key, value) => MapEntry(key.toString(), value.toString()),
           ) ??
           {},
+      repeaterBatteryChemistryByPublicKey:
+          (json['repeater_battery_chemistry_by_public_key'] as Map?)?.map(
+            (key, value) => MapEntry(key.toString(), value.toString()),
+          ) ??
+          {},
     );
   }
 
@@ -125,6 +136,7 @@ class AppSettings {
     Object? languageOverride = _unset,
     bool? appDebugLogEnabled,
     Map<String, String>? batteryChemistryByDeviceId,
+    Map<String, String>? repeaterBatteryChemistryByPublicKey,
   }) {
     return AppSettings(
       clearPathOnMaxRetry: clearPathOnMaxRetry ?? this.clearPathOnMaxRetry,
@@ -154,6 +166,9 @@ class AppSettings {
       appDebugLogEnabled: appDebugLogEnabled ?? this.appDebugLogEnabled,
       batteryChemistryByDeviceId:
           batteryChemistryByDeviceId ?? this.batteryChemistryByDeviceId,
+      repeaterBatteryChemistryByPublicKey:
+          repeaterBatteryChemistryByPublicKey ??
+              this.repeaterBatteryChemistryByPublicKey,
     );
   }
 }