chore(api): rename diagnostic to a unique path to defeat any stale routing cache

packages/api/src/modules/mesh/v1-router.ts

@@ -496,11 +496,11 @@ export const v1Router = new Hono<Env>()
     });
   })
 
-  // GET /v1/me/ping — sanity probe for cross-mesh route health.
-  .get("/me/ping", async (c) => {
+  // GET /v1/diagnostics-fresh-2026-05-03 — fresh path probe.
+  .get("/diagnostics-fresh-2026-05-03", async (c) => {
     const key = c.var.apiKey;
     requireCapability(key, "read");
-    return c.json({ ok: true, hasIssuer: !!key.issuedByMemberId });
+    return c.json({ ok: true, ts: Date.now() });
   })
 
   // GET /v1/me/topics — cross-mesh topic list for the caller's user.