docs: publish real testnet CONTRACT_ID and add repo description

Deploy and initialize the escrow contract on Stellar testnet (admin =
freshly generated deployer key, usdc_token = a deployed mock USDC SAC,
fee_bps = 100), verified live on Stellar Expert. The CONTRACT_ID
previously in .env.development was a non-existent placeholder address
(confirmed invalid on Stellar Expert) left over from earlier scaffolding.

Also sets the GitHub repo description (was empty).

Author: Mystery-CLI

.env.development

@@ -1,6 +1,7 @@
 STELLAR_NETWORK=TESTNET
 HORIZON_URL=https://horizon-testnet.stellar.org
-CONTRACT_ID=CA7QYNF7SOWQ3GLR2BGMZEHXAVIRZA4KVWLTJJFC7MGXUA74P7UJVSGZ
+CONTRACT_ID=CA7SKFUZAWMLVWPGBX6PYDFZTUBOTY76MXOBSBA2F2GV5LGCIG5BUXBZ
+USDC_TOKEN_ADDRESS=CBUHAYBECGWXHG66MJHICF5LZYLOUH64FL5WDU47GAPU4X65BCIC73ZD
 DATABASE_URL=postgres://user:password@localhost:5432/stellar_escrow_dev
 NODE_ENV=development
 PORT=3000

README.md

@@ -2,6 +2,18 @@
 
 Decentralized escrow on Stellar/Soroban Network.
 
+## Deployed Contract (Testnet)
+
+| | |
+|---|---|
+| **CONTRACT_ID** | [`CA7SKFUZAWMLVWPGBX6PYDFZTUBOTY76MXOBSBA2F2GV5LGCIG5BUXBZ`](https://stellar.expert/explorer/testnet/contract/CA7SKFUZAWMLVWPGBX6PYDFZTUBOTY76MXOBSBA2F2GV5LGCIG5BUXBZ) |
+| **Network** | Stellar Testnet |
+| **Admin** | `GAVWQNFKICCVKG7JSA5BK3L2S4Z6BDD3FVB5BBAJ46FUPPLIASFJPDH4` |
+| **Test USDC token** | [`CBUHAYBECGWXHG66MJHICF5LZYLOUH64FL5WDU47GAPU4X65BCIC73ZD`](https://stellar.expert/explorer/testnet/contract/CBUHAYBECGWXHG66MJHICF5LZYLOUH64FL5WDU47GAPU4X65BCIC73ZD) |
+| **Fee** | 100 bps (1%) |
+
+Verify directly on [Stellar Expert](https://stellar.expert/explorer/testnet/contract/CA7SKFUZAWMLVWPGBX6PYDFZTUBOTY76MXOBSBA2F2GV5LGCIG5BUXBZ) — the deploy and `initialize` transactions are both on-chain and public.
+
 ## Features
 ✅ Trade creation form (preview + confirm)
 ✅ Buyer funding flow (USDC approval + tx confirmation)