Added basic clap CLI with subcommand stubs

Cargo.toml

@@ -4,3 +4,4 @@ version = "0.1.0"
 edition = "2024"
 
 [dependencies]
+clap = { version = "4.5", features = ["derive", "env"] }

src/main.rs

@@ -1,3 +1,50 @@
+use clap::{ArgGroup, Parser, Subcommand};
+use std::path::PathBuf;
+
+/// Analyze CI and best practices across Rust project repos
+#[derive(Parser)]
+#[command(name = "crabwatch", version, about, long_about = None)]
+struct Cli {
+    /// Increase logging verbosity
+    #[arg(short, long, action = clap::ArgAction::Count, global = true)]
+    verbose: u8,
+
+    /// Directory where downloaded workflows are cached
+    #[arg(long, global = true)]
+    cache_dir: Option<PathBuf>,
+
+    /// GitHub token
+    #[arg(long, env = "GITHUB_TOKEN", hide_env_values = true, global = true)]
+    github_token: Option<String>,
+
+    #[command(subcommand)]
+    command: Command,
+}
+
+#[derive(Subcommand)]
+enum Command {
+    /// Analyze a repository or an organization
+    #[command(group(ArgGroup::new("target").required(true).args(["repo", "org"])))]
+    Analyze {
+        /// Analyze a single repository
+        #[arg(long)]
+        repo: Option<String>,
+
+        /// Analyze every repository in an organization
+        #[arg(long)]
+        org: Option<String>,
+
+        /// Specific check to run (runs all if omitted)
+        #[arg(long)]
+        check: Option<String>,
+    },
+}
+
 fn main() {
-    println!("Hello, world!");
+    let cli = Cli::parse();
+    match cli.command {
+        Command::Analyze { repo, org, check } => {
+            println!("analyze repo={repo:?} org={org:?} check={check:?}");
+        }
+    }
 }