feat: add visual feedback for CalDAV save & sync actions

- Show spinner + loading text while request is in progress
- Display success (green) or error (red) message, auto-clears after 3s
- Save and Sync have independent feedback rows (both visible at once)
- Fix CaldavTextInput theming and add secureTextEntry for password
- Reset CustomTextInput cursor to start when unfocused

apps/client/src/app/(tabs)/settings.tsx

@@ -1,4 +1,4 @@
-import { Text, View } from "react-native";
+import { ActivityIndicator, Text, View } from "react-native";
 import BaseBackground from "../../components/BaseBackground";
 import BaseButton, { BaseButtonProps } from "../../components/BaseButton";
 import { useThemeStore } from "../../stores/ThemeStore";
@@ -8,7 +8,7 @@ import { Ionicons } from "@expo/vector-icons";
 import { SimpleHeader } from "../../components/Header";
 import { THEMES } from "../../Themes";
 import CustomTextInput from "../../components/CustomTextInput";
-import { useState } from "react";
+import { useCallback, useRef, useState } from "react";
 import { CaldavConfigService } from "../../services/CaldavConfigService";
 import { useCaldavConfigStore } from "../../stores";
 
@@ -33,25 +33,54 @@ type CaldavTextInputProps = {
   title: string;
   value: string;
   onValueChange: (text: string) => void;
+  secureTextEntry?: boolean;
 };
 
 const CaldavTextInput = ({
   title,
   value,
   onValueChange,
+  secureTextEntry,
 }: CaldavTextInputProps) => {
+  const { theme } = useThemeStore();
   return (
     <View className="flex flex-row items-center py-1">
-      <Text className="ml-4 w-24">{title}:</Text>
+      <Text className="ml-4 w-24" style={{ color: theme.textPrimary }}>{title}:</Text>
       <CustomTextInput
         className="flex-1 mr-4 px-3 py-2"
         text={value}
         onValueChange={onValueChange}
+        secureTextEntry={secureTextEntry}
       />
     </View>
   );
 };
 
+type Feedback = { text: string; isError: boolean; loading: boolean };
+
+const FeedbackRow = ({ feedback }: { feedback: Feedback | null }) => {
+  const { theme } = useThemeStore();
+  if (!feedback) return null;
+  return (
+    <View className="flex flex-row items-center justify-center mt-2 mx-4 gap-2">
+      {feedback.loading && (
+        <ActivityIndicator size="small" color={theme.textMuted} />
+      )}
+      <Text
+        style={{
+          color: feedback.loading
+            ? theme.textMuted
+            : feedback.isError
+              ? theme.rejectButton
+              : theme.confirmButton,
+        }}
+      >
+        {feedback.text}
+      </Text>
+    </View>
+  );
+};
+
 const CaldavSettings = () => {
   const { theme } = useThemeStore();
   const { config, setConfig } = useCaldavConfigStore();
@@ -59,18 +88,51 @@ const CaldavSettings = () => {
   const [serverUrl, setServerUrl] = useState(config?.serverUrl ?? "");
   const [username, setUsername] = useState(config?.username ?? "");
   const [password, setPassword] = useState(config?.password ?? "");
+  const [saveFeedback, setSaveFeedback] = useState<Feedback | null>(null);
+  const [syncFeedback, setSyncFeedback] = useState<Feedback | null>(null);
+  const saveTimer = useRef<ReturnType<typeof setTimeout> | null>(null);
+  const syncTimer = useRef<ReturnType<typeof setTimeout> | null>(null);
+
+  const showFeedback = useCallback(
+    (
+      setter: typeof setSaveFeedback,
+      timer: typeof saveTimer,
+      text: string,
+      isError: boolean,
+      loading = false,
+    ) => {
+      if (timer.current) clearTimeout(timer.current);
+      setter({ text, isError, loading });
+      if (!loading) {
+        timer.current = setTimeout(() => setter(null), 3000);
+      }
+    },
+    [],
+  );
 
   const saveConfig = async () => {
-    const saved = await CaldavConfigService.saveConfig(
-      serverUrl,
-      username,
-      password,
-    );
-    setConfig(saved);
+    showFeedback(setSaveFeedback, saveTimer, "Speichere Konfiguration...", false, true);
+    try {
+      const saved = await CaldavConfigService.saveConfig(
+        serverUrl,
+        username,
+        password,
+      );
+      setConfig(saved);
+      showFeedback(setSaveFeedback, saveTimer, "Konfiguration wurde gespeichert", false);
+    } catch {
+      showFeedback(setSaveFeedback, saveTimer, "Fehler beim Speichern der Konfiguration", true);
+    }
   };
 
   const sync = async () => {
-    await CaldavConfigService.sync();
+    showFeedback(setSyncFeedback, syncTimer, "Synchronisiere...", false, true);
+    try {
+      await CaldavConfigService.sync();
+      showFeedback(setSyncFeedback, syncTimer, "Synchronisierung erfolgreich", false);
+    } catch {
+      showFeedback(setSyncFeedback, syncTimer, "Fehler beim Synchronisieren", true);
+    }
   };
 
   return (
@@ -99,6 +161,7 @@ const CaldavSettings = () => {
             title="password"
             value={password}
             onValueChange={setPassword}
+            secureTextEntry
           />
         </View>
         <View className="flex flex-row">
@@ -109,6 +172,8 @@ const CaldavSettings = () => {
             Sync
           </BaseButton>
         </View>
+        <FeedbackRow feedback={saveFeedback} />
+        <FeedbackRow feedback={syncFeedback} />
       </View>
     </>
   );

apps/client/src/components/CustomTextInput.tsx

@@ -30,6 +30,7 @@ const CustomTextInput = (props: CustomTextInputProps) => {
       secureTextEntry={props.secureTextEntry}
       autoCapitalize={props.autoCapitalize}
       keyboardType={props.keyboardType}
+      selection={!focused ? { start: 0 } : undefined}
       style={{
         backgroundColor: theme.messageBorderBg,
         color: theme.textPrimary,