fix(auth): re-export interface-only barrel symbols as types for bun dev runs

The auth commands barrel re-exported 4 interface-only symbols (AuthCommandArgs,
ProfileOutput, ListOutput, CommandContext) via a value 'export {}', which bun's
per-file transpile cannot resolve at runtime (the tsc dist elides them, so users
were unaffected). Split them into 'export type {}' so 'bun run dev' / source runs
work.

src/auth/commands/index.ts

@@ -5,14 +5,8 @@
  */
 
 // Types and utilities
-export {
-  AuthCommandArgs,
-  ProfileOutput,
-  ListOutput,
-  CommandContext,
-  parseArgs,
-  formatRelativeTime,
-} from './types';
+export type { AuthCommandArgs, ProfileOutput, ListOutput, CommandContext } from './types';
+export { parseArgs, formatRelativeTime } from './types';
 
 // Command handlers
 export { handleCreate } from './create-command';