Add Pezkuwi SDK UI - Polkadot.js Apps clone

- Clone Polkadot.js Apps repository
- Update package.json with Pezkuwi branding
- Add Pezkuwi endpoint to production chains (wss://pezkuwichain.app:9944)
- Create comprehensive README for SDK UI
- Set up project structure with all packages

Next steps:
- Apply Kurdistan colors (Kesk, Sor, Zer, Spi + Black) to UI theme
- Replace logos with Pezkuwi branding
- Test build and deployment

pezkuwi-sdk-ui/packages/react-hooks/src/useBlockInterval.ts

@@ -0,0 +1,57 @@
+// Copyright 2017-2025 @polkadot/react-hooks authors & contributors
+// SPDX-License-Identifier: Apache-2.0
+
+import type { ApiPromise } from '@polkadot/api';
+import type { BabeGenesisConfiguration } from '@polkadot/types/interfaces/babe';
+
+import { useMemo } from 'react';
+
+import { BN, BN_THOUSAND, BN_TWO, bnMin } from '@polkadot/util';
+
+import { createNamedHook } from './createNamedHook.js';
+import { useApi } from './useApi.js';
+import { A_DAY } from './useBlocksPerDays.js';
+import { useCall } from './useCall.js';
+
+// Some chains incorrectly use these, i.e. it is set to values such as 0 or even 2
+// Use a low minimum validity threshold to check these against
+const THRESHOLD = BN_THOUSAND.div(BN_TWO);
+const DEFAULT_TIME = new BN(6_000);
+
+function calcInterval (api: ApiPromise): BN {
+  return bnMin(A_DAY, (
+    // Babe, e.g. Relay chains (Substrate defaults)
+    api.consts.babe?.expectedBlockTime ||
+    // POW, eg. Kulupu
+    api.consts.difficulty?.targetBlockTime ||
+    // Subspace
+    api.consts.subspace?.expectedBlockTime || (
+      // Check against threshold to determine value validity
+      api.consts.timestamp?.minimumPeriod.gte(THRESHOLD)
+        // Default minimum period config
+        ? api.consts.timestamp.minimumPeriod.mul(BN_TWO)
+        : api.query.parachainSystem
+          // default guess for a parachain
+          ? api.consts.aura?.slotDuration ?? DEFAULT_TIME.mul(BN_TWO)
+          // default guess for others
+          : DEFAULT_TIME
+    )
+  ));
+}
+
+function useBlockIntervalImpl (apiOverride?: ApiPromise | null): BN {
+  const { api } = useApi();
+
+  const currApi = apiOverride || api;
+  const blockTimeAura = useCall<BN>(currApi.call.auraApi?.slotDuration && currApi.call.auraApi.slotDuration, []);
+  const blockTimeBabe = useCall(currApi.call.babeApi?.configuration && currApi.call.babeApi.configuration, [], {
+    transform: (data: BabeGenesisConfiguration | undefined) => data?.slotDuration
+  });
+
+  return useMemo(
+    () => (blockTimeAura || blockTimeBabe) ?? calcInterval(currApi),
+    [blockTimeAura, blockTimeBabe, currApi]
+  );
+}
+
+export const useBlockInterval = createNamedHook('useBlockInterval', useBlockIntervalImpl);