added sig verification contract and mock api

solver/.gitignore

@@ -0,0 +1,2 @@
+node_modules\
+.env

solver/debug.js

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+require("dotenv").config();
+const ethers = require("ethers");
+const fs = require("fs");
+
+async function main() {
+  const provider = new ethers.providers.JsonRpcProvider(process.env.RPC_URL, {
+    chainId: 31337,
+    name: "anvil-local",
+    ensAddress: null,
+  });
+
+  await provider.ready;
+  const wallet = new ethers.Wallet(process.env.PRIVATE_KEY, provider);
+  const contractJson = JSON.parse(
+    fs.readFileSync(
+      "../contracts/out/MessageVerification.sol/MessageVerification.json",
+      "utf8"
+    )
+  );
+  const contract = new ethers.Contract(
+    process.env.CONTRACT_ADDRESS,
+    contractJson.abi,
+    wallet
+  );
+
+  const prefix = "RENEW_NAME";
+  const messages = ["test1", "test2", "test3"];
+  const value = ethers.BigNumber.from("123456789");
+
+  try {
+    const messageHash = ethers.utils.keccak256(
+      ethers.utils.defaultAbiCoder.encode(
+        ["string", "string[]", "uint256"],
+        [prefix, messages, value]
+      )
+    );
+    const signature = await wallet.signMessage(
+      ethers.utils.arrayify(messageHash)
+    );
+    console.log("Messages:", messages);
+    console.log("Value:", value.toString());
+    console.log("Signature:", signature);
+
+    const tx = await contract.verifyAndStoreMessage(messages, value, signature);
+    console.log("Transaction hash:", tx.hash);
+    await tx.wait();
+    console.log("Messages stored successfully!");
+
+    const count = await contract.getUserMessageCount(wallet.address);
+    console.log("Message count:", count.toString());
+
+    const [storedMessages, storedValue] = await contract.getUserMessage(
+      wallet.address,
+      count.sub(1)
+    );
+    console.log("Stored messages:", storedMessages);
+    console.log("Stored value:", storedValue.toString());
+  } catch (error) {
+    console.error("Error:", error);
+    if (error.error) {
+      console.error("Error details:", error.error);
+    }
+  }
+}
+
+main()
+  .then(() => process.exit(0))
+  .catch((error) => {
+    console.error(error);
+    process.exit(1);
+  });