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/tsconfig.node.json

@@ -0,0 +1,20 @@
+{
+  "compilerOptions": {
+    "target": "ES2022",
+    "lib": ["ES2023"],
+    "module": "ESNext",
+    "skipLibCheck": true,
+
+    "moduleResolution": "bundler",
+    "allowImportingTsExtensions": true,
+    "isolatedModules": true,
+    "moduleDetection": "force",
+    "noEmit": true,
+
+    "strict": true,
+    "noUnusedLocals": false,
+    "noUnusedParameters": false,
+    "noFallthroughCasesInSwitch": true
+  },
+  "include": ["vite.config.ts"]
+}