feat: implement local payment QR codes and update AI co-authoring rules

QR codes are now generated locally using the 'qrcode' library for better privacy and reliability.
Updated .agent/rules.md with co-author details and Conventional Commits preference.

Co-authored-by: Antigravity <antigravity@google.com>

app.py

@@ -3,7 +3,10 @@ from pathlib import Path
 from datetime import datetime
 import re
 import time
-from flask import Flask, render_template, g
+import os
+import io
+import qrcode
+from flask import Flask, render_template, g, send_file, request
 
 # Add scripts directory to path to allow importing from it
 scripts_dir = Path(__file__).parent / "scripts"
@@ -14,6 +17,9 @@ from match_payments import reconcile, fetch_sheet_data, fetch_exceptions, normal
 
 app = Flask(__name__)
 
+# Bank account for QR code payments (can be overridden by ENV)
+BANK_ACCOUNT = os.environ.get("BANK_ACCOUNT", "CZ8520100000002800359168")
+
 @app.before_request
 def start_timer():
     g.start_time = time.perf_counter()
@@ -141,20 +147,34 @@ def reconcile_view():
         for m in sorted_months:
             mdata = data["months"].get(m, {"expected": 0, "original_expected": 0, "paid": 0})
             expected = mdata["expected"]
-            original = mdata["original_expected"]
             paid = int(mdata["paid"])
             
-            cell_status = ""
-            if expected == 0 and paid == 0:
-                cell = "-"
-            elif paid >= expected and expected > 0:
-                cell = "OK"
-            elif paid > 0:
-                cell = f"{paid}/{expected}"
-            else:
-                cell = f"UNPAID {expected}"
+            status = "empty"
+            cell_text = "-"
+            amount_to_pay = 0
             
-            row["months"].append(cell)
+            if expected > 0:
+                if paid >= expected:
+                    status = "ok"
+                    cell_text = "OK"
+                elif paid > 0:
+                    status = "partial"
+                    cell_text = f"{paid}/{expected}"
+                    amount_to_pay = expected - paid
+                else:
+                    status = "unpaid"
+                    cell_text = f"UNPAID {expected}"
+                    amount_to_pay = expected
+            elif paid > 0:
+                status = "surplus"
+                cell_text = f"PAID {paid}"
+            
+            row["months"].append({
+                "text": cell_text,
+                "status": status,
+                "amount": amount_to_pay,
+                "month": month_labels[m]
+            })
             
         row["balance"] = data["total_balance"] # Updated to use total_balance
         formatted_results.append(row)
@@ -178,7 +198,8 @@ def reconcile_view():
         debts=debts,
         unmatched=unmatched,
         attendance_url=attendance_url,
-        payments_url=payments_url
+        payments_url=payments_url,
+        bank_account=BANK_ACCOUNT
     )
 
 @app.route("/payments")
@@ -221,5 +242,36 @@ def payments():
         payments_url=payments_url
     )
 
+@app.route("/qr")
+def qr_code():
+    account = request.args.get("account", BANK_ACCOUNT)
+    amount = request.args.get("amount", "0")
+    message = request.args.get("message", "")
+    
+    # QR Platba standard: SPD*1.0*ACC:accountNumber*BC:bankCode*AM:amount*CC:CZK*MSG:message
+    acc_parts = account.split('/')
+    if len(acc_parts) == 2:
+        acc_str = f"{acc_parts[0]}*BC:{acc_parts[1]}"
+    else:
+        acc_str = account
+
+    try:
+        amt_val = float(amount)
+        amt_str = f"{amt_val:.2f}"
+    except ValueError:
+        amt_str = "0.00"
+
+    # Message max 60 characters
+    msg_str = message[:60]
+    
+    qr_data = f"SPD*1.0*ACC:{acc_str}*AM:{amt_str}*CC:CZK*MSG:{msg_str}"
+    
+    img = qrcode.make(qr_data)
+    buf = io.BytesIO()
+    img.save(buf, format='PNG')
+    buf.seek(0)
+    
+    return send_file(buf, mimetype='image/png')
+
 if __name__ == "__main__":
     app.run(debug=True, host='0.0.0.0', port=5001)