Worker: escape \n in loading-page renderLog so JS is valid

Inside loadingPage()'s template literal, .join('\n') was being
interpreted by the outer TS template — emitting a literal newline
inside a JS string in the rendered HTML. That makes the JS a syntax
error, so dispatch() never fires and the loading page sticks on
"Triggering mining job…" with elapsed frozen at 00:00. Visitors
never got mined because the trigger never happened.

Fix: use '\\n' so the rendered JS contains '\n' (a real escape).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: pirate

cloudflare/worker/index.ts

@@ -840,7 +840,7 @@ function renderLog(lines) {
               : /^>>/.test(l) ? "l-hdr"
               : "";
     return '<span class="' + cls + '">' + esc(l) + '</span>';
-  }).join("\n");
+  }).join("\\n");
   $log.style.display = "block";
   $log.scrollTop = $log.scrollHeight;
 }