Fix JIT nil-param crash: guard execute-request, restore error logging

- orchestration.sx: add nil guard for verb/url before calling do-fetch
  (prevents "Expected string, got nil" when verb info dict lacks method)
- sx_browser.ml: restore JIT error logging (Eval_error only, not all
  exceptions) so real failures are visible, silence routine fallbacks
- Rebuild WASM bundle with fixes

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

web/orchestration.sx

@@ -97,7 +97,7 @@
                 (if (and prompt-msg (nil? prompt-val))
                   (promise-resolve nil)
                   ;; Validation gate
-                  (if (not (validate-for-request el))
+                  (if (or (nil? verb) (nil? url) (not (validate-for-request el)))
                     (promise-resolve nil)
                     (do-fetch el verb verb url
                       (if prompt-val