feat(tui): tambah command /todo dan /usage untuk buka overlay

Overlay Todo dan Usage sebelumnya tidak punya trigger sama sekali di
jalur interaksi normal (cuma bisa lewat restore snapshot sesi) --
sekarang mengikuti pola /workflow yang sudah ada.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/controller/command.rs

@@ -22,6 +22,8 @@ pub enum Command {
     WorkflowRun {
         script: String,
     },
+    TodoOpen,
+    UsageOpen,
     Unknown(String),
 }
 
@@ -75,6 +77,23 @@ pub fn parse_command(text: &str) -> Command {
         "/workflow" => Command::WorkflowRun {
             script: arg1.to_string(),
         },
+        "/todo" => Command::TodoOpen,
+        "/usage" => Command::UsageOpen,
         _ => Command::Unknown(cmd.to_string()),
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn parses_todo_open() {
+        assert_eq!(parse_command("/todo"), Command::TodoOpen);
+    }
+
+    #[test]
+    fn parses_usage_open() {
+        assert_eq!(parse_command("/usage"), Command::UsageOpen);
+    }
+}