feat: Add environment setup command

Adds `weevil setup` with two modes:
- System setup: installs default SDKs and dependencies
- Project setup: reads .weevil.toml and installs project requirements

Provides platform-specific installation instructions when auto-install fails.
Never leaves users wondering what to do next.

src/main.rs

@@ -33,6 +33,12 @@ enum Commands {
         android_sdk: Option<String>,
     },
     
+    /// Setup development environment (system or project)
+    Setup {
+        /// Path to project directory (optional - without it, sets up system)
+        path: Option<String>,
+    },
+    
     /// Upgrade an existing project to the latest generator version
     Upgrade {
         /// Path to the project directory
@@ -99,6 +105,9 @@ fn main() -> Result<()> {
         Commands::New { name, ftc_sdk, android_sdk } => {
             commands::new::create_project(&name, ftc_sdk.as_deref(), android_sdk.as_deref())
         }
+        Commands::Setup { path } => {
+            commands::setup::setup_environment(path.as_deref())
+        }
         Commands::Upgrade { path } => {
             commands::upgrade::upgrade_project(&path)
         }