Remove the local fork

"Fork Locally" ran the selected chain in the browser through
@acala-network/chopsticks-core, which brings its own @polkadot stack
(types, rpc-provider, util-crypto 13 and 14) and @polkadot/wasm-crypto
7.5.4 with the crate versions pezkuwi-wasm 7.5.21 moved off. The app
shipped that second wasm twice, next to ours, for a developer tool;
chopsticks itself stays available from the command line.

Gone: the button, the overlay, the "Local" mock-account modal and the
chopsticks account group, the fork path in the API context, and their
69 locale strings. Mock accounts a fork left in a browser's keyring are
address-only; they now show with the test accounts.

yarn.lock: 32 @polkadot and 2 @acala-network entries -> 0.

packages/react-hooks/src/ctx/types.ts

@@ -1,7 +1,6 @@
 // Copyright 2017-2026 @pezkuwi/react-hooks authors & contributors
 // SPDX-License-Identifier: Apache-2.0
 
-import type { Blockchain } from '@acala-network/chopsticks-core';
 import type { ApiPromise } from '@pezkuwi/api';
 import type { SubmittableExtrinsicFunction } from '@pezkuwi/api/promise/types';
 import type { Signer as InjectedSigner } from '@pezkuwi/api/types';
@@ -40,7 +39,6 @@ export interface ApiState {
   apiDefaultTx: SubmittableExtrinsicFunction;
   apiDefaultTxSudo: SubmittableExtrinsicFunction;
   chainSS58: number;
-  fork: Blockchain | null;
   hasInjectedAccounts: boolean;
   isApiReady: boolean;
   isDevelopment: boolean;
@@ -67,7 +65,6 @@ export interface ApiProps extends ApiState {
   isApiConnected: boolean;
   isApiInitialized: boolean;
   isWaitingInjected: boolean;
-  isLocalFork?: boolean;
 }
 
 export interface Accounts {