Initial commit: bookkeeping skill

Receipt-image to Google Sheets expense logger with HKD conversion.
Includes SKILL.md, categories/schema reference, config template,
and Python scripts for FX conversion (frankfurter.app) and Sheets append.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

scripts/fx_convert.py

@@ -0,0 +1,46 @@
+#!/usr/bin/env python3
+"""
+fx_convert.py <amount> <currency> [--date yyyy-mm-dd]
+
+Convert a given amount in <currency> to HKD.
+Prints one tab-separated line: <hkd_amount>\t<fx_rate>\t<fx_date>
+Non-zero exit on failure.
+
+Uses frankfurter.app by default: free, no API key, ECB reference rates,
+historical dates supported via /{date} path.
+"""
+from __future__ import annotations
+
+import argparse
+import json
+import sys
+import urllib.request
+from datetime import date
+
+
+def fetch_rate(currency: str, on_date: str) -> tuple[float, str]:
+    currency = currency.upper()
+    if currency == "HKD":
+        return 1.0, on_date
+    url = f"https://api.frankfurter.app/{on_date}?from={currency}&to=HKD"
+    with urllib.request.urlopen(url, timeout=10) as resp:
+        data = json.loads(resp.read())
+    rate = data["rates"]["HKD"]
+    return float(rate), data["date"]
+
+
+def main() -> int:
+    ap = argparse.ArgumentParser()
+    ap.add_argument("amount", type=float)
+    ap.add_argument("currency")
+    ap.add_argument("--date", default=date.today().isoformat())
+    args = ap.parse_args()
+
+    rate, fx_date = fetch_rate(args.currency, args.date)
+    hkd = round(args.amount * rate, 2)
+    print(f"{hkd}\t{rate}\t{fx_date}")
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main())