feat: add user reset-apikey command

Adds `hf user reset-apikey <username>` to regenerate a user API key.
Requires user.manage permission. Returns the new key (shown once only).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

internal/help/surface.go

@@ -40,6 +40,7 @@ func CommandSurface() []Group {
 				{Name: "activate", Description: "Activate a user", Permitted: has(perms, "user.manage")},
 				{Name: "deactivate", Description: "Deactivate a user", Permitted: has(perms, "user.manage")},
 				{Name: "delete", Description: "Delete a user", Permitted: has(perms, "user.manage")},
+				{Name: "reset-apikey", Description: "Reset a user's API key", Permitted: has(perms, "user.manage")},
 			},
 		},
 		{