Fix mobile app submodule initialization and cleanup

- Removed incorrect swingmusic_mobile directory
- Properly initialized swingmusic_mobile submodule from swingmusic-mobile.git
- Clean submodule configuration for unified release workflow

swingmusic_mobile/macos/Runner/Configs/AppInfo.xcconfig

@@ -1,14 +0,0 @@
-// Application-level settings for the Runner target.
-//
-// This may be replaced with something auto-generated from metadata (e.g., pubspec.yaml) in the
-// future. If not, the values below would default to using the project name when this becomes a
-// 'flutter create' template.
-
-// The application's name. By default this is also the title of the Flutter window.
-PRODUCT_NAME = swingmusic_mobile
-
-// The application's bundle identifier
-PRODUCT_BUNDLE_IDENTIFIER = com.dvorinka.swingmusic.swingmusicMobile
-
-// The copyright displayed in application information
-PRODUCT_COPYRIGHT = Copyright © 2026 com.dvorinka.swingmusic. All rights reserved.

swingmusic_mobile/macos/Runner/Configs/Debug.xcconfig

@@ -1,2 +0,0 @@
-#include "../../Flutter/Flutter-Debug.xcconfig"
-#include "Warnings.xcconfig"

swingmusic_mobile/macos/Runner/Configs/Release.xcconfig

@@ -1,2 +0,0 @@
-#include "../../Flutter/Flutter-Release.xcconfig"
-#include "Warnings.xcconfig"

swingmusic_mobile/macos/Runner/Configs/Warnings.xcconfig

@@ -1,13 +0,0 @@
-WARNING_CFLAGS = -Wall -Wconditional-uninitialized -Wnullable-to-nonnull-conversion -Wmissing-method-return-type -Woverlength-strings
-GCC_WARN_UNDECLARED_SELECTOR = YES
-CLANG_UNDEFINED_BEHAVIOR_SANITIZER_NULLABILITY = YES
-CLANG_WARN_UNGUARDED_AVAILABILITY = YES_AGGRESSIVE
-CLANG_WARN__DUPLICATE_METHOD_MATCH = YES
-CLANG_WARN_PRAGMA_PACK = YES
-CLANG_WARN_STRICT_PROTOTYPES = YES
-CLANG_WARN_COMMA = YES
-GCC_WARN_STRICT_SELECTOR_MATCH = YES
-CLANG_WARN_OBJC_REPEATED_USE_OF_WEAK = YES
-CLANG_WARN_OBJC_IMPLICIT_RETAIN_SELF = YES
-GCC_WARN_SHADOW = YES
-CLANG_WARN_UNREACHABLE_CODE = YES