reject dictionary lines whose only quote is the last char

[Medios-lgtm]

ParseAFLDictionary only rejects a missing closing quote when stop == start, but when the opening quote is the last character of a line (e.g. kw=" in a --dictionary file) stop ends at start - 1, so stop - start wraps to SIZE_MAX and StrReplaceAll scans past the line buffer before throwing an uncaught std::length_error; checking stop <= start rejects it like the other malformed lines.

[gemini-code-assist]

Code Review

This pull request fixes a potential out-of-bounds or invalid string_view creation in ParseAFLDictionary by updating the boundary check from stop == start to stop <= start. It also adds corresponding unit tests to verify the behavior with invalid inputs containing single or misplaced double quotes. There are no review comments to address, so no additional feedback is provided.