feat: Implement account deletion feature with UI and API integration

mobile-app/composeApp/src/androidMain/kotlin/de/tsschulz/tt_tagebuch/app/ui/AppRoot.kt

@@ -5972,8 +5972,10 @@ private fun SettingsScreen(
     }
     val authState by dependencies.authManager.state.collectAsState()
     val clubState by dependencies.clubManager.state.collectAsState()
+    val androidContext = LocalContext.current
     var sessionStatus by rememberSaveable { mutableStateOf<String?>(null) }
     var isLoading by rememberSaveable { mutableStateOf(false) }
+    var showDeleteAccountDialog by rememberSaveable { mutableStateOf(false) }
     val sessionValidMessage = tr("mobile.sessionValid", "Session gültig")
     val sessionInvalidMessage = tr("mobile.sessionInvalid", "Session ungültig")
     val sessionCheckFailedMessage = tr("mobile.sessionCheckFailed", "Session check fehlgeschlagen")
@@ -6084,11 +6086,22 @@ private fun SettingsScreen(
             ) { Text(tr("billing.title", "Abrechnung")) }
         }
         SectionTitle(tr("mobile.legal", "Rechtliches"))
-        Text(
-            tr("mobile.legalInAppTodo", "Impressum/Datenschutz: in-App-Ansicht folgt (kein Browser-Aufruf)."),
-            style = MaterialTheme.typography.caption,
-            modifier = Modifier.padding(bottom = 4.dp),
-        )
+        TextButton(
+            onClick = {
+                androidContext.startActivity(
+                    Intent(Intent.ACTION_VIEW, Uri.parse("${dependencies.apiConfig.baseUrl}/datenschutz")),
+                )
+            },
+            modifier = Modifier.fillMaxWidth(),
+        ) { Text("Datenschutzerklärung") }
+        TextButton(
+            onClick = {
+                androidContext.startActivity(
+                    Intent(Intent.ACTION_VIEW, Uri.parse("${dependencies.apiConfig.baseUrl}/impressum")),
+                )
+            },
+            modifier = Modifier.fillMaxWidth(),
+        ) { Text("Impressum") }
         Button(
             onClick = {
                 isLoading = true
@@ -6134,6 +6147,17 @@ private fun SettingsScreen(
             Text(tr("auth.logout", "Abmelden"))
         }
 
+        SectionTitle("Konto und Daten")
+        OutlinedButton(
+            onClick = { showDeleteAccountDialog = true },
+            modifier = Modifier
+                .fillMaxWidth()
+                .padding(top = 8.dp)
+                .heightIn(min = TouchMinHeight),
+        ) {
+            Text("Eigenes Konto löschen", color = MaterialTheme.colors.error)
+        }
+
         OutlinedButton(
             onClick = {
                 dependencies.applicationScope.launch {
@@ -6149,6 +6173,73 @@ private fun SettingsScreen(
             Text(tr("club.change", "Verein wechseln"))
         }
     }
+
+    if (showDeleteAccountDialog) {
+        DeleteAccountDialog(
+            onDismiss = { showDeleteAccountDialog = false },
+            onConfirm = { password, onError ->
+                dependencies.applicationScope.launch {
+                    runCatching {
+                        dependencies.authManager.deleteAccount(password)
+                        dependencies.clubManager.clearSelection()
+                        dependencies.diaryManager.clear()
+                        dependencies.membersManager.clear()
+                        dependencies.trainingStatsManager.clear()
+                        dependencies.scheduleManager.clear()
+                        dependencies.pendingApprovalsManager.clear()
+                        dependencies.permissionsAdminManager.clear()
+                        dependencies.apiLogsManager.clear()
+                        dependencies.clubInternalTournamentsManager.clear()
+                        dependencies.officialTournamentsReadManager.clear()
+                    }.onSuccess {
+                        showDeleteAccountDialog = false
+                    }.onFailure {
+                        onError(it.message ?: "Konto konnte nicht gelöscht werden.")
+                    }
+                }
+            },
+        )
+    }
+}
+
+@Composable
+private fun DeleteAccountDialog(
+    onDismiss: () -> Unit,
+    onConfirm: (password: String, onError: (String) -> Unit) -> Unit,
+) {
+    var password by rememberSaveable { mutableStateOf("") }
+    var error by rememberSaveable { mutableStateOf<String?>(null) }
+    AlertDialog(
+        onDismissRequest = onDismiss,
+        title = { Text("Eigenes Konto löschen") },
+        text = {
+            Column {
+                Text("Diese Aktion löscht dein Benutzerkonto, deine Login-Sessions, Vereinszuordnungen und personenbezogene Integrationsdaten. Geteilte Vereinsdaten bleiben erhalten.")
+                error?.let { Text(it, color = MaterialTheme.colors.error, modifier = Modifier.padding(top = 8.dp)) }
+                OutlinedTextField(
+                    value = password,
+                    onValueChange = { password = it },
+                    label = { Text("Passwort zur Bestätigung") },
+                    modifier = Modifier.fillMaxWidth().padding(top = 8.dp),
+                    singleLine = true,
+                )
+            }
+        },
+        confirmButton = {
+            TextButton(
+                onClick = {
+                    if (password.isBlank()) {
+                        error = "Bitte Passwort eingeben."
+                    } else {
+                        onConfirm(password) { error = it }
+                    }
+                },
+            ) { Text("Endgültig löschen", color = MaterialTheme.colors.error) }
+        },
+        dismissButton = {
+            TextButton(onClick = onDismiss) { Text("Abbrechen") }
+        },
+    )
 }
 
 @Composable