Add multisig pending-operations UI, fix broken multisig address calc, new signing portal

- calculateMultisigAddress was completely broken (hex-decoded an SS58 string
  and never hashed the preimage) - fixed via @pezkuwi/util-crypto's real
  encodeMultiAddress/createKeyMulti, verified against the actual known
  multisig address on-chain.
- ReservesDashboardPage had stale Noter/Berdevk addresses that don't match
  the real signers - centralized as BRIDGE_MULTISIG_SPECIFIC_ADDRESSES.
- USDTBridge withdrawal called assets.burn directly as a single-signer
  extrinsic (always fails - only the multisig is Admin) while only
  checking status.isFinalized (a failed dispatch is still finalized, so it
  silently did nothing) - replaced with the correct transfer-to-custody
  flow the relayer actually watches for.
- New MultisigOperationsPage (/multisig/pending) lists pending calls from
  real Multisig.Multisigs storage and lets any of the 5 signers
  approve/reject with their own wallet extension.
- New standalone sign/ app (deployed separately at
  pezbridge-sign.pex.mom) - a dedicated, gated signing portal for the same
  operations, so signing isn't dependent on this app alone.

sign/package.json

@@ -0,0 +1,30 @@
+{
+  "name": "pezbridge-sign",
+  "private": true,
+  "version": "1.0.0",
+  "type": "module",
+  "description": "Dedicated, minimal-surface signing portal for PezkuwiChain multisig operations - gated to known signatory addresses only.",
+  "scripts": {
+    "dev": "vite",
+    "build": "tsc -b && vite build",
+    "preview": "vite preview"
+  },
+  "dependencies": {
+    "react": "^18.3.1",
+    "react-dom": "^18.3.1",
+    "@pezkuwi/api": "^16.5.36",
+    "@pezkuwi/extension-dapp": "^0.62.20",
+    "@pezkuwi/extension-inject": "^0.62.20",
+    "@pezkuwi/keyring": "^14.0.25",
+    "@pezkuwi/util": "^14.0.25",
+    "@pezkuwi/util-crypto": "^14.0.25"
+  },
+  "devDependencies": {
+    "@types/react": "^18.3.12",
+    "@types/react-dom": "^18.3.1",
+    "@vitejs/plugin-react-swc": "^3.5.0",
+    "typescript": "^5.6.3",
+    "vite": "^5.4.10",
+    "vite-plugin-node-polyfills": "^0.22.0"
+  }
+}