refactor(cli): centralize process lifecycle

packages/cli/src/utils/commandUsageResolution.ts

@@ -0,0 +1,32 @@
+import type { CommandDef } from "citty";
+
+type LazyCommandDef = CommandDef | (() => CommandDef | Promise<CommandDef>);
+
+export interface ResolvedCommandUsage {
+  command: CommandDef;
+  parent?: CommandDef;
+}
+
+async function loadSubcommand(command: CommandDef, name: string): Promise<CommandDef | undefined> {
+  const subcommands = command.subCommands as Record<string, LazyCommandDef> | undefined;
+  const candidate = subcommands?.[name];
+  if (!candidate) return undefined;
+  return typeof candidate === "function" ? candidate() : candidate;
+}
+
+/** Resolve the deepest adjacent citty subcommand named by argv. */
+export async function resolveCommandUsage(
+  root: CommandDef,
+  argv: readonly string[],
+): Promise<ResolvedCommandUsage> {
+  let command = root;
+  let parent: CommandDef | undefined;
+  for (const argument of argv) {
+    if (argument.startsWith("-")) break;
+    const child = await loadSubcommand(command, argument);
+    if (!child) break;
+    parent = command;
+    command = child;
+  }
+  return { command, parent };
+}