feat(settings): add participant name input to Jam settings

- Add participant name text input in Group Jam > Identity section
- User can now set custom display name for Jam rooms instead of auto-generated 'Host-XXXX' / 'Guest-XXXX'
- Persists to UserSettings.jamParticipantName

Resolves: #3182 (participant name not editable)

composeApp/src/commonMain/composeResources/values/strings.xml

@@ -319,6 +319,8 @@
     <string name="settings_jam_broker_password">Password (optional)</string>
     <string name="settings_jam_broker_client_id">Client ID prefix</string>
     <string name="settings_jam_broker_client_id_subtitle">Used to identify this Spotube instance</string>
+    <string name="settings_jam_participant_name">Participant name</string>
+    <string name="settings_jam_participant_name_placeholder">Your display name in jam rooms</string>
     <string name="settings_jam_broker_tls_subtitle">Encrypt the broker connection</string>
     <string name="settings_jam_broker_diagnostics_subtitle">Check the current broker settings before starting a room.</string>
     <string name="settings_jam_broker_test">Test connection</string>

composeApp/src/commonMain/kotlin/org/spotube/spotube/modules/settings/JamSettingsScreen.kt

@@ -58,6 +58,8 @@ import spotube.composeapp.generated.resources.settings_jam_broker_content_descri
 import spotube.composeapp.generated.resources.settings_jam_broker_username_placeholder
 import spotube.composeapp.generated.resources.settings_jam_broker_test_fail
 import spotube.composeapp.generated.resources.jam_error_connection_failed
+import spotube.composeapp.generated.resources.settings_jam_participant_name
+import spotube.composeapp.generated.resources.settings_jam_participant_name_placeholder
 
 @Composable
 fun JamSettingsScreen(
@@ -197,6 +199,23 @@ internal fun JamSettingsContent(
             settingsSectionHeader(Res.string.settings_jam_section_identity)
             settingsSectionCard(
                 items = listOf(
+                    {
+                        TextInputSettingCard(
+                            title = stringResource(Res.string.settings_jam_participant_name),
+                            value = uiState.settings.jamParticipantName,
+                            placeholder = stringResource(Res.string.settings_jam_participant_name_placeholder),
+                            onValueSaved = { name ->
+                                viewModel.update {
+                                    copy(jamParticipantName = name)
+                                }
+                            },
+                            icon = {
+                                SettingsItemIcon(
+                                    Iconsax.User,
+                                    stringResource(Res.string.settings_jam_participant_name)
+                                )
+                            })
+                    },
                     {
                         TextInputSettingCard(
                             title = stringResource(Res.string.settings_jam_broker_client_id),