fix: bw/stats 404, gateway links, history crash

- swr.ts: remove useBandwidth(), drop bw from useDashboard()
- events/route.ts: skip bandwidth SSE (Kubo 0.28.0 unsupported)
- usage/page.tsx: remove getBWStats call + bw references
- helpers.ts: gatewayLink -> ipfs.maos.dedyn.io (subdomain only)
- upload/page.tsx: fix local gatewayLink (subdomain only)
- storage.ts: update default gatewayUrl, add defensive getHistory()

graphify-out/cost.json

@@ -0,0 +1,12 @@
+{
+  "runs": [
+    {
+      "date": "2026-06-27T12:47:45.586275+00:00",
+      "input_tokens": 0,
+      "output_tokens": 0,
+      "files": 37
+    }
+  ],
+  "total_input_tokens": 0,
+  "total_output_tokens": 0
+}