feat: private STRK/USDC convert via AVNU

docs/architecture.md

@@ -30,6 +30,7 @@ flowchart TB
 | Wallet | starknet.js 10, get-starknet discovery 6, Ready. Connect on desktop via the injected picker. Connect on phone inside Ready's in-app browser |
 | Actions | `strk20InvokeTransaction` in `src/lib/escrow.ts` |
 | Helper | Cairo `privacy_invoke` escrow in `cairo/` |
+| Private swaps | AVNU's deployed executor for shielded STRK ↔ USDC, quoted from AVNU's public API and batched in `src/lib/avnu.ts` |
 | Pool | Official STRK20 pool on Mainnet and Sepolia. Addresses live in `src/utils/constants.ts` |
 
 ## What the helper does

docs/judging.md

@@ -22,6 +22,7 @@ How far into the stack, not how many buzzwords.
 | Shielded balances | Yes, via the user's Ready wallet. The dapp does not read or display a counterparty balance | Account shield/unshield in the PWA; Pay spends shielded notes |
 | Private transfers into app logic | Yes. Pay, claim, and cancel are `strk20InvokeTransaction` batches | `src/lib/escrow.ts` |
 | Anonymizer contract | Yes. Custom `privacy_invoke` escrow: Deposit, Claim, Cancel | `cairo/src/lib.cairo` |
+| Private swaps | Yes. Shielded STRK ↔ USDC via AVNU's deployed executor, batched as `strk20InvokeTransaction` actions | `src/lib/avnu.ts` |
 | Privacy SDK | No, on purpose. A marketplace must not hold viewing keys | Wallet API route only |
 | Stealth / shadow accounts | No. A different STRK20 surface, not needed for the cash-like promise | See [Architecture](architecture.md) |
 

package.json

@@ -9,8 +9,10 @@
     "lint": "eslint ."
   },
   "dependencies": {
+    "@avnu/avnu-sdk": "^4.2.0",
     "@starknet-io/get-starknet-discovery": "6.0.2",
     "@starknet-io/get-starknet-wallet-standard": "6.0.2",
+    "ethers": "^6.15.0",
     "next": "^16.0.8",
     "qrcode": "1.5.3",
     "react": "19.2.1",