Given a sentence containing mixed case and punctuation, and a syllable dictionary mapping lowercase words to their syllable counts, implement find_haiku(sentence: str, syllable_dict: dict) -> list[str] | None that returns the first contiguous three-line haiku with 5, 7, and 5 syllables respectively. Treat tokens case-insensitively for dictionary lookups and strip leading/trailing punctuation when matching keys, but preserve the original tokens’ casing and punctuation when returning the three lines. The lines must be formed by partitioning a single contiguous subsequence of words into three consecutive segments that sum to 5, 7, and 5 syllables. If no such subsequence exists, return None. Aim for O(N) time (e.g., prefix sums + hashing) and state space complexity. Discuss edge cases such as unknown words, apostrophes (e.g., "don't"), trailing punctuation, and multiple spaces.