fix: derive submit solution actor wallet from claim

apps/web/src/app/api/mcp/[tool]/route.ts

@@ -168,7 +168,7 @@ export async function POST(request: NextRequest, props: { params: Promise<{ tool
       case "submit_solution": {
         const parsed = SubmitSolutionRequestSchema.parse(body);
         
-        const submission = await prisma.$transaction(async (tx) => {
+        const result = await prisma.$transaction(async (tx) => {
           const claim = await tx.claim.findUnique({ where: { claim_token: parsed.claim_token } });
           if (!claim || claim.task_id !== parsed.task_id || claim.status !== TaskStatus.EXECUTING) {
             throw new Error("Invalid claim token or claim is not EXECUTING");
@@ -207,15 +207,19 @@ export async function POST(request: NextRequest, props: { params: Promise<{ tool
             afterState: { status: TaskStatus.VERIFYING }
           });
           
-          return newSubmission;
+          return {
+            submission: newSubmission,
+            claim,
+          };
         });
+        const { submission, claim: submittedClaim } = result;
 
         void sendTrafficAlert({
           level: "info",
           action: "EXTERNAL_SUBMIT_SOLUTION_SUCCESS",
           surface: "mcp/submit_solution",
           actorType: "AGENT",
-          actorId: parsed.developer_wallet,
+          actorId: submittedClaim.developer_wallet,
           taskId: submission.task_id,
           message: `Agent 提交解法: ${parsed.task_id}`,
           metadata: {