feat(maestro): show only the program on session cards

The command fragment named the full command line, so a session spawned
with `claude --dangerously-skip-permissions` spent the whole line on a
flag. Cards now name the program only — its icon in the web client, its
bare name in the TUI — and keep the full command line in the tooltip.

Adds `maestro_protocol::display::command_program`, the Rust counterpart
of the web's `splitCommand`.

web/src/attach.ts

@@ -56,12 +56,13 @@ export interface AttachInfo {
   command: string;
 }
 
-/** Header echoes the sidebar: the command's leading program becomes its tool
- * icon when we have a mark for it, remaining words stay as text. */
+/** Header echoes the sidebar: the program becomes its tool icon when we have a
+ * mark for it and stays as its bare name when we do not. Arguments are
+ * dropped, as on the card. */
 function commandFragment(command: string): string {
-  const { tool, rest } = splitCommand(command);
+  const { tool, program } = splitCommand(command);
   const icon = tool ? toolIconSvg(tool) : null;
-  const text = icon ? rest : command;
+  const text = icon ? "" : program;
   return `<span class="at-cmd">${icon ?? ""}${text ? escapeHtml(text) : ""}</span>`;
 }