feat: add AfterCoin (AFC) private blockchain for Minecraft casino

Private Ethereum chain (Clique PoA, chain ID 8888) with ERC-20 token
(0 decimals, 1 AFC = 1 diamond) bridging casino balances on-chain so
players can view tokens in MetaMask.

- Geth v1.13.15 node with 5s block time, zero gas cost
- AfterCoin ERC-20 contract with owner-gated mint/burn/bridgeTransfer
- Bridge API (Express + ethers.js + SQLite) with register, deposit,
  withdraw, balance, and wallet endpoints
- Nonce queue for serial transaction safety
- Auto-deploys contract on first boot
- Updated mainframe Lua with diff-based on-chain sync (pcall fallback)
- Updated card generator Lua with wallet info display

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

services/afc-bridge/package.json

@@ -0,0 +1,15 @@
+{
+  "name": "afc-bridge",
+  "version": "1.0.0",
+  "description": "AfterCoin bridge API - syncs Minecraft casino balances to private Ethereum chain",
+  "main": "src/index.js",
+  "scripts": {
+    "start": "node src/index.js",
+    "deploy": "node src/deploy.js"
+  },
+  "dependencies": {
+    "express": "^4.21.0",
+    "ethers": "^6.13.0",
+    "better-sqlite3": "^11.0.0"
+  }
+}