Add signature providers

Requires: common-ci-configuration!75 (merged)

ts/packages/signers-keychain/src/index.ts

 import type { IOnlineSignatureProvider, ITransaction, TAccountName, TRole } from "@hiveio/wax";
-import { WaxError } from "@hiveio/wax";
 
 import { KeychainKeyTypes, KeychainSDK } from "keychain-sdk";
 
-const keychain = new KeychainSDK(window);
-
 const mapRoles: Record<TRole, KeychainKeyTypes | undefined> = {
   active: KeychainKeyTypes.active,
   posting: KeychainKeyTypes.posting,
@@ -12,7 +9,8 @@ const mapRoles: Record<TRole, KeychainKeyTypes | undefined> = {
   memo: KeychainKeyTypes.memo
 };
 
-export class WaxKeychainProviderError extends WaxError {}
+// We do not extend from WaxError to avoid runtime dependencies, such as: /vite or /web - without it we can import only types
+export class WaxKeychainProviderError extends Error {}
 
 /**
  * Wax transaction signature provider using the Keychain SDK.
@@ -36,12 +34,17 @@ export class WaxKeychainProviderError extends WaxError {}
 class KeychainProvider implements IOnlineSignatureProvider {
   private readonly role: KeychainKeyTypes;
 
+  private static keychain: KeychainSDK;
+
   private constructor(
     private readonly accountName: TAccountName,
     role: TRole
   ) {
     if (!mapRoles[role])
-      throw new WaxKeychainProviderError(`Role ${role} is not supported by the Wax signature provider: ${KeychainProvider.name}`);
+      throw new Error(`Role ${role} is not supported by the Wax signature provider: ${KeychainProvider.name}`);
+
+    if(!KeychainProvider.keychain)
+      KeychainProvider.keychain = new KeychainSDK(window);
 
     this.role = mapRoles[role];
   }
@@ -51,7 +54,7 @@ class KeychainProvider implements IOnlineSignatureProvider {
   }
 
   public async signTransaction(transaction: ITransaction): Promise<void> {
-    const data = await keychain.signTx({
+    const data = await KeychainProvider.keychain.signTx({
       method: mapRoles[this.role]!,
       username: this.accountName,
       tx: JSON.parse(transaction.toLegacyApi())