Add scores to Wordlist

Wordlists are currently just lists of words that don't take scores into account, besides an optional score threshold when reading from a wordlist file. A better filling algorithm could prioritize words with higher scores.

Start by tracing the Wordlist representation, the wordlist-file reader and the filling algorithm mentioned in the issue. Compare the existing score-threshold behavior with how candidates are selected, then define and test what it means for higher-scored words to be prioritized during filling.

由索引模型根據 Issue 內容生成。