refactor(design-system): consolidate components and standardize naming with Ms prefix

- Removed redundant files: `AppFooter`, `AppHeader`, `AppScaffold`, `LoadingIndicator`, `MeldestelleButton`, `MeldestelleTextField`, `DashboardCard`.
- Introduced `MsFooter`, `MsHeader`, `MsScaffold`, `MsLoadingIndicator`, `MsButton`, `MsTextField`, `MsCard` with standardized implementation and naming.
- Updated references in `profile-feature` and `ping-feature` to use the new components.
- Aligned with roadmap goals for a consistent, reusable, and high-density design system.

Signed-off-by: Stefan Mogeritsch <stefan.mo.co@gmail.com>

frontend/features/profile-feature/src/commonMain/kotlin/at/mocode/frontend/features/profile/presentation/ProfileScreen.kt

@@ -13,9 +13,9 @@ import androidx.compose.runtime.*
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.unit.dp
-import at.mocode.frontend.core.designsystem.components.LoadingIndicator
-import at.mocode.frontend.core.designsystem.components.MeldestelleButton
-import at.mocode.frontend.core.designsystem.components.MeldestelleTextField
+import at.mocode.frontend.core.designsystem.components.MsButton
+import at.mocode.frontend.core.designsystem.components.MsLoadingIndicator
+import at.mocode.frontend.core.designsystem.components.MsTextField
 
 @Composable
 fun ProfileScreen(
@@ -37,7 +37,7 @@ fun ProfileScreen(
     )
 
     if (uiState.isLoading) {
-      LoadingIndicator(modifier = Modifier.align(Alignment.CenterHorizontally))
+      MsLoadingIndicator(modifier = Modifier.align(Alignment.CenterHorizontally))
     } else {
       // Fehleranzeige
       uiState.errorMessage?.let { error ->
@@ -100,7 +100,7 @@ fun ZnsLinkSection(
 
       Spacer(Modifier.height(16.dp))
 
-      MeldestelleTextField(
+      MsTextField(
         value = satznummer,
         onValueChange = { satznummer = it },
         label = "ZNS Satznummer",
@@ -112,7 +112,7 @@ fun ZnsLinkSection(
 
       Spacer(Modifier.height(16.dp))
 
-      MeldestelleButton(
+      MsButton(
         onClick = { onLink(satznummer) },
         text = "Jetzt verknüpfen",
         isLoading = isLinking,
@@ -154,7 +154,7 @@ fun ProfileDetailsSection(
       Spacer(Modifier.height(12.dp))
 
       if (isEditing) {
-        MeldestelleTextField(
+        MsTextField(
           value = contactEmail,
           onValueChange = { contactEmail = it },
           label = "Kontakt E-Mail",
@@ -162,7 +162,7 @@ fun ProfileDetailsSection(
           leadingIcon = Icons.Default.Email
         )
         Spacer(Modifier.height(12.dp))
-        MeldestelleTextField(
+        MsTextField(
           value = bio,
           onValueChange = { bio = it },
           label = "Info / Bio",