Implement complete GPS speedometer functionality

Features implemented:
- Real-time GPS speed tracking with permission handling
- Customizable speed units (km/h, mph) with persistent settings
- Digital and analog speedometer display styles
- Dark/light theme support with system integration
- Optional metrics: coordinates, distance, trip time, GPS accuracy
- Trip reset functionality and error handling
- Modular architecture with Provider state management

Technical details:
- Added dependencies: geolocator, permission_handler, provider, shared_preferences
- Configured Android location permissions (FINE_LOCATION, COARSE_LOCATION)
- Portrait orientation lock for mobile-first experience
- Extensible settings system for future customization options
- Clean separation of concerns: providers, screens, widgets

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

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

windows/flutter/generated_plugin_registrant.cc

@@ -6,6 +6,12 @@
 
 #include "generated_plugin_registrant.h"
 
+#include <geolocator_windows/geolocator_windows.h>
+#include <permission_handler_windows/permission_handler_windows_plugin.h>
 
 void RegisterPlugins(flutter::PluginRegistry* registry) {
+  GeolocatorWindowsRegisterWithRegistrar(
+      registry->GetRegistrarForPlugin("GeolocatorWindows"));
+  PermissionHandlerWindowsPluginRegisterWithRegistrar(
+      registry->GetRegistrarForPlugin("PermissionHandlerWindowsPlugin"));
 }