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/.graphify_labels.json

@@ -0,0 +1 @@
+{"0": "Portal Layout & Navigation", "1": "Landing & Payment UI", "2": "Payment Smart Contract", "3": "IPFS Gateway & History", "4": "Explorer Components", "5": "NPM Dependencies", "6": "TypeScript Config", "7": "API Routes & Proxy", "8": "File Preview", "9": "Static Server", "10": "Root Layout", "11": "Sidebar Navigation", "12": "Deploy Script", "13": "Next.js Config", "14": "Playwright Config", "15": "PostCSS Config", "16": "E2E Tests"}