Add explicit logging for route decisions in bind-event

- Log "sx:route server fetch <url>" when falling back to network
- Use console.error for eval errors (not console.warn)
- Restructure bind-event to separate client route check from &&-chain

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

shared/sx/ref/bootstrap_js.py

@@ -2630,7 +2630,7 @@ PLATFORM_ORCHESTRATION_JS = """
       }
       return sxRenderWithEnv(source, merged);
     } catch (e) {
-      console.warn("sx:route eval error", e);
+      console.error("[sx-ref] sx:route eval error for:", source, e);
       return NIL;
     }
   }