fix(shortcuts): 注册测试补全 pm 域以支持 Wiki 等全部命令域

- 将 pm 加入 expectedGroups，使 TestRegisterAll 与 25 个已注册命令域一致
- 确保 wiki/file/snippet 等 HEAD-only 分组在测试中继续被校验

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

shortcuts/register_test.go

@@ -14,7 +14,7 @@ func TestRegisterAll(t *testing.T) {
 		"repo", "issue", "label", "license", "pr", "profile", "release", "branch",
 		"org", "user", "search", "ci", "workflow",
 		"compare", "member", "milestone", "pipeline", "webhook",
-		"dataset", "health", "ignore",
+		"dataset", "health", "ignore", "pm",
 		// HEAD-only groups preserved during the upstream/master merge.
 		"file", "snippet", "wiki",
 	}