Fix readline buffer limit (10MB) and evaluator spec filename

- ocaml_bridge: 10MB readline buffer for large spec explorer responses
- nav-data: evaluator.sx filename (was eval.sx, actual spec file is evaluator.sx)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

shared/static/scripts/sx-browser.js

@@ -14,7 +14,7 @@
   // =========================================================================
 
   var NIL = Object.freeze({ _nil: true, toString: function() { return "nil"; } });
-  var SX_VERSION = "2026-03-18T13:07:01Z";
+  var SX_VERSION = "2026-03-18T19:18:46Z";
 
   function isNil(x) { return x === NIL || x === null || x === undefined; }
   function isSxTruthy(x) { return x !== false && !isNil(x); }