Address @qa review on PR #12 (issue #11)

- index.html: replace Image() probe with fetch(no-cors) + AbortController
  timeout. fetch resolves for any network response (incl. 4xx/5xx) so
  resolve -> 'up', reject/timeout -> 'down'. Fixes the bug where 401/404
  services were marked green.
- services.json: add Homepage service under 'dev' (was missing; the
  homepage is one of the public homelab services). Now 21 services.
- services.json: fix ethereum category icon (' Ξ' -> 'Ξ') leading space.
- .gitignore (new): ignore /.playwright-mcp/ and services-page.png.
- git rm --cached the three stray dev artifacts so they leave the repo.

index.html

@@ -81,13 +81,14 @@
         done = true;
         setStatusDot(dot, state);
       }
-      var img = new Image();
-      img.onload = function () { settle("up"); };
-      img.onerror = function () { settle("up"); };
-      img.onloadstart = function () {};
-      var timeout = setTimeout(function () { settle("down"); }, 6000);
-      img.src = url + "?_probe=" + Date.now();
-      window.addEventListener("beforeunload", function () { clearTimeout(timeout); });
+      var controller = window.AbortController ? new AbortController() : null;
+      var timeout = setTimeout(function () {
+        if (controller) controller.abort();
+        settle("down");
+      }, 6000);
+      fetch(url, { mode: "no-cors", cache: "no-store", redirect: "follow", signal: controller ? controller.signal : undefined })
+        .then(function () { clearTimeout(timeout); settle("up"); })
+        .catch(function () { clearTimeout(timeout); settle("down"); });
     }
 
     fetch(src)