feat(portal): wire DashboardPage to live Chain-138 RPC + SolaceScan Explorer

- Add services/{http,chain138,explorer,proxmox,dbisCore} + hooks/{useLiveChain,useOnChainBalances}
- Add BackendStatusBar + LiveNetworkPanel components on DashboardPage
- Overlay on-chain META balance on account rows carrying a walletAddress
- Normalize EIP-55 checksum in chain138.getNativeBalance so hand-typed
  sample custody addresses (e.g. 0x742d35Cc...bD38) don't silently drop
  out of the balance map
- Default RPC: https://rpc.d-bis.org (user-preferred gateway)
- proxmox.ts stays mocked (CF-Access, needs BFF); dbisCore.ts stays
  mocked (no public deployment yet)

Co-Authored-By: Nakamoto, S <defi@defi-oracle.io>

src/hooks/useOnChainBalances.ts

@@ -0,0 +1,51 @@
+import { useEffect, useRef, useState } from 'react';
+import { getNativeBalances, type OnChainBalance } from '../services/chain138';
+
+export interface OnChainBalancesState {
+  balances: Record<string, OnChainBalance>;
+  loading: boolean;
+  error: string | null;
+  lastUpdated: Date | null;
+}
+
+/**
+ * Fetches native Chain-138 balances for the given addresses and re-polls
+ * every `pollMs` (default 30s). Addresses array must be stable — pass a
+ * memoized list, or the hook will re-fetch on every render.
+ */
+export function useOnChainBalances(addresses: string[], pollMs = 30_000): OnChainBalancesState {
+  const [balances, setBalances] = useState<Record<string, OnChainBalance>>({});
+  const [loading, setLoading] = useState(addresses.length > 0);
+  const [error, setError] = useState<string | null>(null);
+  const [lastUpdated, setLastUpdated] = useState<Date | null>(null);
+  const mounted = useRef(true);
+
+  const key = addresses.join(',');
+
+  useEffect(() => {
+    mounted.current = true;
+    if (addresses.length === 0) { setLoading(false); return; }
+    let cancelled = false;
+
+    const tick = async () => {
+      try {
+        const result = await getNativeBalances(addresses);
+        if (cancelled || !mounted.current) return;
+        setBalances(result);
+        setError(null);
+        setLastUpdated(new Date());
+      } catch (e) {
+        if (cancelled || !mounted.current) return;
+        setError(e instanceof Error ? e.message : String(e));
+      } finally {
+        if (!cancelled && mounted.current) setLoading(false);
+      }
+    };
+    void tick();
+    const id = setInterval(tick, pollMs);
+    return () => { cancelled = true; mounted.current = false; clearInterval(id); };
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [key, pollMs]);
+
+  return { balances, loading, error, lastUpdated };
+}