Decode Ambiguous Morse Messages

You are given a mapping from Morse patterns to lowercase English letters. Implement two related functions: 1. **Deterministic decoding with character and word separators** - Input: a Morse-encoded string, a `char_sep` that separates letters inside a word, and a `word_sep` that separates words. - Output: the decoded sentence. - Example: if `char_sep` separates letters and `word_sep` separates words, decode the full message by splitting on words first and then on characters. 2. **Enumerate all valid decodings when character separators are missing** - Input: a Morse-encoded string that contains only a `word_sep` between encoded words, but no separator between letters inside each word. - Because each encoded word may be partitioned into letters in multiple valid ways, return **all possible decoded sentences** as a list or set. - For each encoded word, generate every valid letter sequence whose Morse concatenation matches that word exactly, then combine the per-word results into full-sentence outputs. Assume the Morse-to-letter dictionary is provided as part of the problem.