fix(tools): enforce string schema lengths by Unicode code point

CHANGELOG.md

@@ -15,6 +15,8 @@
   the five borough cores load and `CCTV_NYC_MAX_SOURCES` changes the cap. The catalog-wide ceiling is
   unchanged; extra cameras share it round-robin with the other packs.
 
+- Tool string length validation counts Unicode characters correctly, including characters outside the basic multilingual plane.
+
 - Treat explicitly current, complete empty vessel coverage as a successful update,
   clearing obsolete contacts while retaining stale or incomplete snapshots.