Add QR payment generator with live Medicus price list

- New QRPlatba/ module: standalone app for generating SPAYD QR payment codes
- Live price list loaded directly from Medicus Firebird DB (VLV_SEL), sorted by KOD
- Patient data (name, surname, RC) passed as arguments from Medicus button
- Auto-generates QR on load and refreshes on every dropdown change
- Account selector dropdown (two FIO accounts with IBAN)
- Save button exports QR as PNG next to the EXE (sys.executable-relative path)
- SPAYD format: ACC, AM, CC, X-VS (rodné číslo), MSG (patient + item)
- README.md with full documentation, Medicus button command, DB schema
- Add .gitignore (excludes build/, dist/, .venv/, .idea/, .claude/)

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

.gitignore

@@ -0,0 +1,21 @@
+# Python
+__pycache__/
+*.py[cod]
+*.pyo
+
+# Virtual environment
+.venv/
+
+# PyInstaller build artifacts
+build/
+dist/
+*.spec
+
+# IDE
+.idea/
+
+# Claude
+.claude/
+
+# Output folders
+QRPlatby/