test(05-01): scaffold routing workspace with failing contract suite

- fifth npm workspace @araharah/routing (buildless TS, search/ precedent)
- root delegates routing:test / routing:typecheck / routing:corpus
- C1-C6 RED: contract gates fail while src/types.ts + seed are absent

routing/test/harness.mjs

@@ -0,0 +1,10 @@
+/*
+ * harness.mjs — zero-dependency test registry.
+ * Same hand-rolled shape as bot/test/harness.mjs (the Phase 2 precedent):
+ * suites import { test } and register async cases; runner.mjs drains the registry.
+ */
+const tests = [];
+export function test(name, fn) {
+  tests.push({ name, fn });
+}
+export const registry = tests;