Add min stake amount to the staking module

The minimum amount of BTC deposit should be taken from  `BitcoinDepositor` contract. The amount is in tBTC token precision before export this value in SDK has to be converted to satoshi precision.

sdk/src/lib/contracts/bitcoin-depositor.ts

@@ -35,4 +35,9 @@ export interface BitcoinDepositor extends DepositorProxy {
    * @param extraData Encoded extra data.
    */
   decodeExtraData(extraData: string): DecodedExtraData
+
+  /**
+   * @returns Minimum stake amount.
+   */
+  minStake(): Promise<bigint>
 }

sdk/src/lib/ethereum/bitcoin-depositor.ts

@@ -128,6 +128,14 @@ class EthereumBitcoinDepositor
 
     return { staker, referral }
   }
+
+  /**
+   * @see {BitcoinDepositor#minStake}
+   * @dev The value in tBTC token precision (1e18 precision).
+   */
+  async minStake(): Promise<bigint> {
+    return this.instance.minStake()
+  }
 }
 
 export { EthereumBitcoinDepositor, packRevealDepositParameters }

sdk/src/modules/staking/index.ts

@@ -2,6 +2,7 @@ import { ChainIdentifier, TBTC } from "@keep-network/tbtc-v2.ts"
 import { AcreContracts, DepositorProxy } from "../../lib/contracts"
 import { ChainEIP712Signer } from "../../lib/eip712-signer"
 import { StakeInitialization } from "./stake-initialization"
+import { toSatoshi } from "../../lib/utils"
 
 /**
  * Module exposing features related to the staking.
@@ -78,6 +79,14 @@ class StakingModule {
   estimatedBitcoinBalance(identifier: ChainIdentifier) {
     return this.#contracts.stBTC.assetsBalanceOf(identifier)
   }
+
+  /**
+   * @returns Minimum stake amount in 1e8 satoshi precision.
+   */
+  async minStakeAmount() {
+    const value = await this.#contracts.bitcoinDepositor.minStake()
+    return toSatoshi(value)
+  }
 }
 
 export { StakingModule, StakeInitialization }

sdk/test/utils/mock-acre-contracts.ts

@@ -13,6 +13,7 @@ export class MockAcreContracts implements AcreContracts {
       decodeExtraData: jest.fn(),
       encodeExtraData: jest.fn(),
       revealDeposit: jest.fn(),
+      minStake: jest.fn(),
     } as BitcoinDepositor
 
     this.stBTC = {