Implement trie-based autocomplete

Problem

Design an autocomplete data structure using a trie.

You must support:

1. insert(word: string) -> void
2. search(word: string) -> bool (exact match)
3. startsWith(prefix: string) -> bool
4. suggest(prefix: string, limit: int) -> list[string] returning up to limit words that start with prefix .

Notes / Constraints

• Words contain lowercase English letters a-z .
• suggest may return results in any deterministic order (e.g., lexicographic) as long as it is consistent.
• Aim for typical trie complexities: O(L) for insert/search where L is string length; suggest should be proportional to output size (plus traversal).

Edge cases

• Duplicate inserts.
• Empty prefix.
• Prefix that matches no words.