Initial commit: Pezkuwi SDK UI

Comprehensive web interface for interacting with Pezkuwi blockchain.

Features:
- Blockchain explorer
- Wallet management
- Staking interface
- Governance participation
- Developer tools

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

packages/page-staking2/src/Validators/useHeartbeat.ts

@@ -0,0 +1,56 @@
+// Copyright 2017-2026 @pezkuwi/app-staking authors & contributors
+// SPDX-License-Identifier: Apache-2.0
+
+import type { Option, u32 } from '@pezkuwi/types';
+import type { Codec } from '@pezkuwi/types/types';
+import type { SessionInfo, Validator } from '../types.js';
+import type { UseHeartbeat } from './types.js';
+
+import { useMemo } from 'react';
+
+import { createNamedHook, useApi, useCall } from '@pezkuwi/react-hooks';
+import { isBoolean, isNumber } from '@pezkuwi/util';
+
+import { useCacheMap } from '../useCache.js';
+
+const EMPTY: UseHeartbeat = {};
+
+const OPT_BLOCKS = {
+  transform: (authoredBlocks: u32): number =>
+    authoredBlocks.toNumber()
+};
+
+const OPT_BEATS = {
+  // Option<WrapperOpaque<PalletImOnlineBoundedOpaqueNetworkState>>
+  transform: (receivedHeartbeats: Option<Codec>): boolean =>
+    receivedHeartbeats.isSome
+};
+
+function useHeartbeatImpl ({ stashId, stashIndex }: Validator, { currentSession }: SessionInfo): UseHeartbeat {
+  const { api } = useApi();
+
+  const params = useMemo(
+    () => stashIndex === -1
+      ? undefined
+      : currentSession && ({
+        authoredBlocks: [currentSession, stashId],
+        receivedHeartbeats: [currentSession, stashIndex]
+      }),
+    [currentSession, stashId, stashIndex]
+  );
+
+  const authoredBlocks = useCall(params && api.query.imOnline.authoredBlocks, params?.authoredBlocks, OPT_BLOCKS);
+  const receivedHeartbeats = useCall(params && api.query.imOnline.receivedHeartbeats, params?.receivedHeartbeats, OPT_BEATS);
+
+  const result = useMemo(
+    () => isNumber(authoredBlocks) && isBoolean(receivedHeartbeats) && ({
+      authoredBlocks,
+      isOnline: !!(authoredBlocks || receivedHeartbeats)
+    }),
+    [authoredBlocks, receivedHeartbeats]
+  );
+
+  return useCacheMap('useHeartbeat', stashId, result) || EMPTY;
+}
+
+export default createNamedHook('useHeartbeat', useHeartbeatImpl);