SIWE auth, API proxy fixes, dashboard, login, usage pages

- SIWE auth flow: challenge/login/logout/me API routes + JWT middleware
- Fixed [...path] catch-all: Kubo proxy with matchRoute() + mapToKuboAPI()
- Fixed session_id → nonce field mismatch in AuthProvider
- Fixed dashboard pins crash: Kubo returns {Keys: {...}}, not array
- Added middleware route guard (307 redirect to /login)
- Added login, register, profile, usage, upload pages
- Added dashboard components (StorageGauge, FreeTierProgress)
- Added SWR hooks + AuthGuard + Providers + Toast/ErrorBoundary
- Added payment integration (smart contract ABI, tiers, tokens)
- Fixed IPNS key listing: Name/Id → name/id mapping
- Added PWA support (manifest, service worker, icons)
- Added tests for helpers, limits, search-index, wallet

src/app/dashboard/components/StorageGauge.tsx

@@ -0,0 +1,43 @@
+'use client';
+
+/* ════════════════════════════ StorageGauge ════════════════════════════ */
+
+interface StorageGaugeProps {
+  usedGB: number;
+  maxGB: number;
+  label?: string;
+}
+
+export default function StorageGauge({ usedGB, maxGB, label = 'Storage' }: StorageGaugeProps) {
+  const pct = maxGB > 0 ? Math.min((usedGB / maxGB) * 100, 100) : 0;
+  const color =
+    pct > 90 ? 'bg-accent-rose' : pct > 70 ? 'bg-accent-amber' : 'bg-accent-cyan';
+
+  const textColor =
+    pct > 90 ? 'text-accent-rose' : pct > 70 ? 'text-accent-amber' : 'text-accent-cyan';
+
+  return (
+    <div className="glass rounded-xl p-5">
+      <div className="flex items-center justify-between mb-2">
+        <span className="text-xs text-surface-400">{label}</span>
+        <span className={`text-xs font-mono font-medium ${textColor}`}>
+          {usedGB.toFixed(1)} / {maxGB.toFixed(1)} GB
+        </span>
+      </div>
+      <div className="h-2.5 rounded-full bg-surface-700 overflow-hidden">
+        <div
+          className={`h-full rounded-full transition-all duration-700 ease-out ${color}`}
+          style={{ width: `${pct}%` }}
+        />
+      </div>
+      <div className="flex justify-between mt-1.5">
+        <span className="text-[10px] text-surface-500">{pct.toFixed(0)}% gebruikt</span>
+        {pct > 80 && (
+          <span className="text-[10px] text-accent-rose flex items-center gap-1">
+            ⚠️ Bijna vol
+          </span>
+        )}
+      </div>
+    </div>
+  );
+}