Use this when you need an exact line-level diff between two blocks of text instead of eyeballing the differences.

Use this when you need an exact line-level diff between two blocks of text instead of eyeballing the differences. Deterministic: same input, same output. Computes a longest-common-subsequence diff and returns every line tagged added, removed, or unchanged, plus per-category counts. Example: original "a\nb", modified "a\nB" -> added 1, removed 1, unchanged 1, with lines [{type:"unchanged",text:"a"},{type:"removed",text:"b"},{type:"added",text:"B"}]. Trailing edits produce separate removed+added lines rather than an in-place change. Inputs whose line-count product exceeds 4,000,000 are rejected as too large to diff.