feat(web): add PEZMessage on-chain E2E encrypted messaging UI

- x25519 ECDH + XChaCha20-Poly1305 encryption via @noble libs
- Key derivation from wallet signRaw, private key held in memory only
- Messaging pallet integration (registerEncryptionKey, sendMessage, inbox)
- Inbox polling every 12s, auto-decrypt when key unlocked
- ComposeDialog with recipient key validation and 512-byte limit
- Settings moved from grid to nav bar gear icon, PEZMessage takes its slot
- i18n translations for all 6 languages (en, tr, kmr, ckb, ar, fa)

web/src/lib/messaging/chain.ts

@@ -0,0 +1,88 @@
+import type { ApiPromise } from '@pezkuwi/api';
+import { hexToBytes, bytesToHex } from './crypto';
+
+export interface EncryptedMessage {
+  sender: string;
+  blockNumber: number;
+  ephemeralPublicKey: Uint8Array;
+  nonce: Uint8Array;
+  ciphertext: Uint8Array;
+}
+
+// --- Storage queries ---
+
+export async function getEncryptionKey(
+  api: ApiPromise,
+  address: string
+): Promise<Uint8Array | null> {
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  const result = await (api.query as any).messaging.encryptionKeys(address);
+  if (result.isNone || result.isEmpty) return null;
+  const hex = result.unwrap().toHex();
+  return hexToBytes(hex);
+}
+
+export async function getCurrentEra(api: ApiPromise): Promise<number> {
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  const era = await (api.query as any).messaging.currentEra();
+  return era.toNumber();
+}
+
+export async function getInbox(
+  api: ApiPromise,
+  era: number,
+  address: string
+): Promise<EncryptedMessage[]> {
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  const result = await (api.query as any).messaging.inbox([era, address]);
+  if (result.isEmpty || result.length === 0) return [];
+
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  return result.map((msg: Record<string, any>) => ({
+    sender: msg.sender.toString(),
+    blockNumber: msg.blockNumber?.toNumber?.() ?? msg.block_number?.toNumber?.() ?? 0,
+    ephemeralPublicKey: hexToBytes(
+      msg.ephemeralPublicKey?.toHex?.() ?? msg.ephemeral_public_key?.toHex?.() ?? '0x'
+    ),
+    nonce: hexToBytes(msg.nonce.toHex()),
+    ciphertext: hexToBytes(msg.ciphertext.toHex()),
+  }));
+}
+
+export async function getSendCount(
+  api: ApiPromise,
+  era: number,
+  address: string
+): Promise<number> {
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  const count = await (api.query as any).messaging.sendCount([era, address]);
+  return count.toNumber();
+}
+
+// --- TX builders ---
+
+export function buildRegisterKeyTx(api: ApiPromise, publicKey: Uint8Array) {
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  return (api.tx as any).messaging.registerEncryptionKey(bytesToHex(publicKey));
+}
+
+export function buildSendMessageTx(
+  api: ApiPromise,
+  recipient: string,
+  ephemeralPubKey: Uint8Array,
+  nonce: Uint8Array,
+  ciphertext: Uint8Array
+) {
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  return (api.tx as any).messaging.sendMessage(
+    recipient,
+    bytesToHex(ephemeralPubKey),
+    bytesToHex(nonce),
+    bytesToHex(ciphertext)
+  );
+}
+
+export function buildAcknowledgeTx(api: ApiPromise) {
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  return (api.tx as any).messaging.acknowledgeMessages();
+}