fix: detect unpunctuated Korean plain endings

src/claridoc/style_contracts.py

@@ -38,7 +38,7 @@ Write Korean reader-facing prose as a supported first-person experience, not as
 - Use conversational but disciplined Korean. A Korean developer should be able to say the sentence naturally to a colleague without turning it into forced colloquial speech.
 """
 
-_PLAIN_FORM_ENDING = re.compile(r"(?<!니)다(?=[.!?](?:\s|$))")
+_PLAIN_FORM_ENDING = re.compile(r"(?<!니)다(?=(?:[.!?](?:\s|$)|$))")
 _FIRST_PERSON = re.compile(r"(?:저는|제가)")
 _FENCE = re.compile(r"^\s*(?:```|~~~)")
 _HEADING = re.compile(r"^\s{0,3}(#{1,6})\s+(.+?)\s*$")