Initial commit: prediction-market arb scanner + GHA alerts

- Monthly + hourly Kalshi/Polymarket arb scanner (stdlib-only Python).
- Live positions tab w/ realized P&L history.
- GitHub Actions cron workflow texts SMS via Apps Script webhook on
  newly-detected arbs. State persisted in alerts_state.json.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

data/secrets.example.json

@@ -0,0 +1,14 @@
+{
+  "_comment": "Copy this file to data/secrets.json and fill in your own values. data/secrets.json is git-ignored. Never share these values.",
+
+  "polymarket_wallet": "0xYOUR_POLYMARKET_PROXY_WALLET_ADDRESS",
+
+  "_kalshi_comment": "Kalshi -> Settings -> API Keys. Create a key, save the private key file locally, put its absolute path + the Key ID here. Read-only is fine.",
+  "kalshi_key_id": "",
+  "kalshi_private_key_path": "",
+
+  "_sms_comment": "Optional SMS alerts. Deploy a tiny Apps Script web app whose doPost reads {message,to,carrier} and calls MailApp.sendEmail(to+'@'+carrier, '', message). Paste its /exec URL below, then your phone (10 digits) and the carrier gateway domain (e.g. vtext.com, tmomail.net, txt.att.net).",
+  "sms_webhook": "",
+  "sms_phone": "",
+  "sms_carrier": ""
+}