Update: Add EUR currency support for Slovak companies

- Modified get_cz_qr_code_base64() to support both CZK and EUR
- Updated cz_to_iban() to better handle international IBANs (SK, etc.)
- SPAYD QR now uses actual invoice currency in CC: field
- Updated manifest description to reflect EUR support
- Updated README with setup instructions for Slovak companies

This allows Slovak companies with EUR accounts to generate SPAYD QR codes
for Czech customers, enabling cross-border EUR payments via mobile banking.

Generated by Mistral Vibe.
Co-Authored-By: Mistral Vibe <vibe@mistral.ai>

README.md

@@ -1,24 +1,81 @@
 🇨🇿 [Česká verze](README.cs.md)
 
-# Czech QR Payments
+# Czech QR Payments (SPAYD)
 
-This module adds QR codes to invoices for quick mobile payments. The codes are in SPAYD format, compatible with all major Czech banking apps.
+This module adds **SPAYD format QR codes** to invoices for quick mobile payments via Czech banking apps. Compatible with all major Czech banks (ČSOB, Komerční banka, Česká spořitelna, Raiffeisenbank, etc.).
 
-* **Bank account format:** Enter Czech bank accounts in the standard Odoo field using the Czech format, e.g., `123-456/0800`
-![Bank Account Entry](static/description/bank_account_en.png)
+## ✅ Supported Features
 
-* **Foreign accounts:** For foreign accounts, you can enter IBAN in the same field (standard Odoo field).
-* **Currency support:** Czech QR codes are generated for invoices in CZK currency. For foreign payments, the original Odoo QR code is preserved.
+* **Bank account formats:**
+  - Czech local format: `123-456/0800` (automatically converted to IBAN)
+  - IBAN format: `CZ6508000000001234567890`, `SK6509000000005123456789`, etc.
+  ![Bank Account Entry](static/description/bank_account_en.png)
+
+* **Currency support:**
+  - ✅ **CZK** - Standard Czech payments
+  - ✅ **EUR** - Cross-border payments (for Slovak companies invoicing Czech customers)
+  - ❌ Other currencies - Not supported (SPAYD is primarily for CZK and EUR)
+
+* **Use cases:**
+  - Czech company invoicing Czech customers in CZK
+  - **Slovak company invoicing Czech customers in EUR** (your use case!)
+  - Any company with a CZ/SK/EU IBAN invoicing Czech customers
+
+## ⚡ Quick Setup for Slovak Companies
+
+If you are a **Slovak company** invoicing **Czech customers in EUR**:
+
+1. **Set up your EUR bank account:**
+   - Go to **Accounting → Configuration → Journals**
+   - Select your bank journal
+   - In the **Bank Account** field, enter your **EUR IBAN** (e.g., `SK6509000000005123456789`)
+   - Set **Currency** to **EUR**
+
+2. **Create invoice for Czech customer:**
+   - Set customer country to **Czech Republic (CZ)**
+   - Set invoice currency to **EUR**
+   - Confirm the invoice (post it)
+
+3. **QR code generates automatically!**
+   - The QR code will be in **SPAYD format** with `CC:EUR`
+   - Czech customers can scan it with their banking app
+   - Payment will be processed in EUR to your account
 
 ## Frequently Asked Questions (FAQ)
 
-**The QR code is not generated on the invoice**
-Make sure you have the **QR Codes** option enabled in the **Invoicing** app configuration.
+**Q: The QR code is not generated on the invoice**
+A: Make sure you have:
+- The **QR Codes** option enabled in the **Invoicing** app configuration
+- A bank account set up for your company with the **same currency as the invoice** (EUR or CZK)
+- The invoice is **confirmed/posted**
 ![QR Code Settings](static/description/qr_payment_settings_en.png)
 
 
-**The QR code is generated on the invoice, but scanning it results in an error**
-Check whether a bank account for the Czech currency is set up for the main company. See "Bank account format" section above.
+**Q: The QR code is generated on the invoice, but scanning it results in an error**
+A: Check whether:
+- A bank account for the **invoice currency** (EUR or CZK) is set up for the company
+- The bank account number is in **valid format** (Czech format `123-456/0800` or IBAN)
+- The customer's banking app supports **SPAYD QR codes**
+
+
+**Q: Can I use EUR currency with this module?**
+A: ✅ **Yes!** This module now supports both **CZK and EUR** currencies. Perfect for Slovak companies invoicing Czech customers in EUR.
+
+
+**Q: Does this work with Slovak (SK) IBAN?**
+A: ✅ **Yes!** The module handles any valid IBAN (SK, CZ, DE, AT, etc.). If your bank account is already an IBAN, it will be used as-is.
+
+
+**Q: Can I use this for invoices in other currencies (USD, GBP)?**
+A: ❌ **No.** The SPAYD standard is designed for CZK and EUR. Other currencies are not supported by Czech banking apps via QR codes.
+
+
+**Q: I'm a Slovak company. Will Czech customers be able to pay EUR invoices via QR code?**
+A: ✅ **Yes**, if:
+- Your bank account is a **EUR account** (Slovak or international)
+- The invoice currency is **EUR**
+- The Czech customer's bank supports **cross-border EUR payments** (most do)
+- The QR code will contain `CC:EUR` and your SK/EUR IBAN
 ---
 
 ## About