Minimal slug test: isolate the normalization rule

To test a slug problem, use a harmless short phrase containing the smallest troublesome feature: an accented letter, punctuation mark, repeated separator, or leading space. Record the exact input characters and expected output. Then verify the generated route under the application's case and Unicode rules. A plain ASCII phrase will not reveal a locale-sensitive bug. If uniqueness is the issue, create a second synthetic title that normalizes to the same slug.