Add SelfieCamTheme with branded colors and settings card containers

- Create SelfieCamTheme.swift with rose/magenta-tinted surface colors
- Add AppSurface, AppAccent, AppStatus, AppBorder typealiases to avoid conflicts
- Wrap settings sections in SettingsCard containers for visual grouping
- Add accentColor parameter to all SegmentedPicker and SettingsToggle usages
- Update all color references to use App-prefixed typealiases
- Background uses AppSurface.primary, cards use AppSurface.card

SelfieCam/Features/Settings/SettingsView.swift

@@ -284,7 +284,8 @@ struct SettingsView: View {
             SegmentedPicker(
                 title: "",
                 options: CameraFlashMode.allCases.map { ($0.displayName, $0) },
-                selection: $viewModel.flashMode
+                selection: $viewModel.flashMode,
+                accentColor: AppAccent.primary
             )
             .accessibilityLabel(String(localized: "Select flash mode"))
         }
@@ -311,7 +312,8 @@ struct SettingsView: View {
             SegmentedPicker(
                 title: "",
                 options: CameraHDRMode.allCases.map { ($0.displayName, $0) },
-                selection: $viewModel.hdrMode
+                selection: $viewModel.hdrMode,
+                accentColor: AppAccent.primary
             )
             .disabled(!isPremiumUnlocked)
             .accessibilityLabel(String(localized: "Select HDR mode"))
@@ -398,7 +400,8 @@ struct SettingsView: View {
                     (String(localized: "Front"), CameraPosition.front),
                     (String(localized: "Back"), CameraPosition.back)
                 ],
-                selection: $viewModel.cameraPosition
+                selection: $viewModel.cameraPosition,
+                accentColor: AppAccent.primary
             )
             .accessibilityLabel(String(localized: "Select camera position"))
         }
@@ -777,9 +780,9 @@ struct SettingsView: View {
             SettingsToggle(
                 title: "Enable Debug Premium",
                 subtitle: "Unlock all premium features for testing",
-                isOn: $viewModel.isDebugPremiumEnabled
+                isOn: $viewModel.isDebugPremiumEnabled,
+                accentColor: AppStatus.warning
             )
-            .tint(AppStatus.warning)
             // Icon Generator
             NavigationLink {
                 IconGeneratorView(config: .selfieCam, appName: "SelfieCam")