fix: strip Solana RPC memo prefix [N] before matching deposits

Solana getSignaturesForAddress returns memo as "[byteLen] actualMemo"
(e.g. "[15] devsol-abc123"). Strip the prefix with regex before
comparing against DB memos. Discovered during live e2e testing.

Author: rz1989s

src/services/deposit.test.ts

@@ -114,8 +114,8 @@ describe('DepositDetector', () => {
     const mockRpcWithDeposit = {
       getSignaturesForAddress: vi.fn(() => ({
         send: vi.fn(async () => [
-          { memo: 'devsol-match1', signature: 'deposit_sig_1' },
-          { memo: 'unrelated-memo', signature: 'other_sig' },
+          { memo: '[15] devsol-match1', signature: 'deposit_sig_1' },
+          { memo: '[16] unrelated-memo', signature: 'other_sig' },
         ]),
       })),
     };
@@ -185,6 +185,35 @@ describe('DepositDetector', () => {
     expect(onDeposit).not.toHaveBeenCalled();
   });
 
+  it('strips Solana RPC memo prefix [N] before matching', async () => {
+    const onDeposit = vi.fn();
+    const tx = db.create({
+      type: 'sell',
+      wallet: 'seller1',
+      sol_amount: 5,
+      usdc_amount: 4.75,
+      memo: 'devsol-prefix1',
+    });
+
+    const mockRpcPrefix = {
+      getSignaturesForAddress: vi.fn(() => ({
+        send: vi.fn(async () => [
+          { memo: '[15] devsol-prefix1', signature: 'prefix_sig' },
+        ]),
+      })),
+    };
+
+    const detector = new DepositDetector({
+      db, rpc: mockRpcPrefix as any, treasuryAddress: 'T', onDeposit,
+    });
+
+    await detector.poll();
+    expect(onDeposit).toHaveBeenCalledWith(
+      expect.objectContaining({ id: tx.id }),
+      'prefix_sig',
+    );
+  });
+
   it('does not match on memo substring', async () => {
     const onDeposit = vi.fn();
     db.create({ type: 'sell', wallet: 'seller1', sol_amount: 5, usdc_amount: 4.75, memo: 'devsol-abc' });

src/services/deposit.ts

@@ -47,8 +47,11 @@ export class DepositDetector {
 
       for (const sig of sigs) {
         if (sig.memo && sig.memo.trim()) {
-          const trimmedMemo = sig.memo.trim();
-          const matching = pendingSells.find((tx) => tx.memo && trimmedMemo === tx.memo);
+          // Solana RPC returns memo as "[byteLen] actualMemo" — strip prefix
+          const rawMemo = sig.memo.trim();
+          const cleanMemo = rawMemo.replace(/^\[\d+\]\s*/, '');
+          if (!cleanMemo) continue;
+          const matching = pendingSells.find((tx) => tx.memo && cleanMemo === tx.memo);
           if (matching) {
             await this.processDeposit(matching.id, sig.signature);
           }