feat(config): add ENV shorthand for environment override

Add support for --dart-define=ENV=dev as a convenience shorthand
alongside the existing ENVIRONMENT override. Maps 'dev'/'local' to
local environment and 'prod'/'production' to production.

Also remove macos Flutter config files from tracking (already in gitignore).

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

+14
lib/config/environment_config.dart
···
static const String _flavor = String.fromEnvironment('FLUTTER_FLAVOR');
/// Explicit environment override via --dart-define=ENVIRONMENT=local
+
/// Also supports --dart-define=ENV=dev for convenience
static const String _envOverride = String.fromEnvironment('ENVIRONMENT');
+
static const String _envShorthand = String.fromEnvironment('ENV');
/// Get current environment based on build configuration
///
···
switch (_envOverride) {
case 'local':
return local;
+
case 'production':
+
return production;
+
}
+
}
+
+
// Priority 1b: Shorthand ENV override (dev -> local, prod -> production)
+
if (_envShorthand.isNotEmpty) {
+
switch (_envShorthand) {
+
case 'dev':
+
case 'local':
+
return local;
+
case 'prod':
case 'production':
return production;
}
-1
macos/Flutter/Flutter-Debug.xcconfig
···
-
#include "ephemeral/Flutter-Generated.xcconfig"
-1
macos/Flutter/Flutter-Release.xcconfig
···
-
#include "ephemeral/Flutter-Generated.xcconfig"