docs: update README for auto-lookback feature and add -a short flag (#8)

crates/claude-chill/src/cli.rs

@@ -1,19 +1,28 @@
 use clap::Parser;
 
 #[derive(Parser, Debug)]
-#[command(name = "claude-chill", version)]
+#[command(
+    name = "claude-chill",
+    version,
+    about = "A PTY proxy that tames Claude Code's massive terminal updates"
+)]
 pub struct Cli {
+    /// Command to run (e.g., "claude")
     pub command: String,
 
+    /// Arguments to pass to the command
     #[arg(trailing_var_arg = true)]
     pub args: Vec<String>,
 
+    /// Max lines stored for lookback (default: 100000)
     #[arg(short = 'H', long = "history")]
     pub history_lines: Option<usize>,
 
+    /// Key to toggle lookback mode, quote to prevent glob expansion (default: "[ctrl][6]")
     #[arg(short = 'k', long = "lookback-key")]
     pub lookback_key: Option<String>,
 
-    #[arg(long = "auto-lookback-timeout")]
+    /// Auto-lookback timeout in ms, 0 to disable (default: 5000)
+    #[arg(short = 'a', long = "auto-lookback-timeout")]
     pub auto_lookback_timeout: Option<u64>,
 }