feat: create validated ZUGFeRD invoices in one console command

jr_einvoice/presets.py

@@ -1,6 +1,8 @@
 from __future__ import annotations
 from pathlib import Path
 import yaml
+from .paths import presets_root
+import re
 
 def load_yaml(path: Path) -> dict:
     if not path.exists():
@@ -18,6 +20,11 @@ def deep_merge(a: dict, b: dict) -> dict:
 
 def load_customer_preset(repo_root: Path, customer_key: str) -> dict:
     key = customer_key.strip().lower()
+    if not re.fullmatch(r"[a-z0-9_-]+", key):
+        raise ValueError("Customer key must contain only letters, digits, _ or -")
+    local = presets_root(repo_root)
+    if (local / "customers" / f"{key}.yaml").is_file():
+        return load_yaml(local / "customers" / f"{key}.yaml")
     # Prefer per-customer file
     file_preset = repo_root / "presets" / "customers" / f"{key}.yaml"
     if file_preset.exists():