Add naming scheme support for genlockes with lineage-aware suggestions (#20)

Genlockes can now select a naming scheme at creation time, which is
automatically applied to every leg's run. When catching a pokemon whose
evolution family appeared in a previous leg, the system suggests the
original nickname with a roman numeral suffix (e.g., "Heracles II").

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

Reviewed-on: TheFurya/nuzlocke-tracker#20
Co-authored-by: Julian Tabel <juliantabel.jt@gmail.com>
Co-committed-by: Julian Tabel <juliantabel.jt@gmail.com>

backend/src/app/services/naming.py

@@ -1,5 +1,6 @@
 import json
 import random
+import re
 from functools import lru_cache
 from pathlib import Path
 
@@ -26,6 +27,42 @@ def get_words_for_category(category: str) -> list[str]:
     return _load_dictionary().get(category, [])
 
 
+_ROMAN_NUMERALS = [
+    (1000, "M"),
+    (900, "CM"),
+    (500, "D"),
+    (400, "CD"),
+    (100, "C"),
+    (90, "XC"),
+    (50, "L"),
+    (40, "XL"),
+    (10, "X"),
+    (9, "IX"),
+    (5, "V"),
+    (4, "IV"),
+    (1, "I"),
+]
+
+_ROMAN_SUFFIX_RE = re.compile(
+    r"\s+(M{0,3}(?:CM|CD|D?C{0,3})(?:XC|XL|L?X{0,3})(?:IX|IV|V?I{0,3}))$"
+)
+
+
+def to_roman(n: int) -> str:
+    """Convert a positive integer to a roman numeral string."""
+    parts: list[str] = []
+    for value, numeral in _ROMAN_NUMERALS:
+        while n >= value:
+            parts.append(numeral)
+            n -= value
+    return "".join(parts)
+
+
+def strip_roman_suffix(name: str) -> str:
+    """Remove a trailing roman numeral suffix from a name (e.g., 'Heracles II' -> 'Heracles')."""
+    return _ROMAN_SUFFIX_RE.sub("", name).strip()
+
+
 def suggest_names(
     category: str,
     used_names: set[str],