register checks via static barrel instead of readdir + dynamic import

Checks keep self-registering on import; src/checks/all.ts imports every
shipped check from the entry's static graph. Keeps the check graph fully
statically resolvable (bundler/loader friendly) and removes the only
dynamic-import discovery in the codebase.

src/checks/all.ts

@@ -0,0 +1,15 @@
+/**
+ * Static barrel for shipped checks.
+ *
+ * Every check module self-registers on import (top-level `registerCheck`), so
+ * importing all of them here — once, statically, from the entry graph —
+ * registers every check before commands bind. Adding a check means dropping
+ * the file in and adding one import line here.
+ */
+import "./comments.js";
+import "./complexity.js";
+import "./dead-code.js";
+import "./deep-modules.js";
+import "./defensive-guards.js";
+import "./scope.js";
+import "./todos.js";