feat(cctv): add Houston TranStar camera pack

Register the keyless TranStar snapshot catalog as a live CCTV source,
synthesize frame URLs from validated numeric camera ids, and keep the
nearest cameras to Houston's metro cores under the existing catalog ceiling.

src/data/dataCredits.js

@@ -300,6 +300,12 @@ export const DATA_CREDITS = [
       'Traffic cameras (Toronto): contains information licensed under the ' +
       '<a href="https://www.toronto.ca/city-government/data-research-maps/open-data/open-data-licence/" target="_blank" rel="noopener">Open Government Licence – Toronto</a>',
   },
+  {
+    key: 'houston-cctv',
+    html:
+      'CCTV cameras &amp; frames (Houston): ' +
+      '<a href="https://traffic.houstontranstar.org/cctv/transtar/" target="_blank" rel="noopener">Houston TranStar</a>',
+  },
   {
     key: 'gbfs',
     html: