## Problem
Email-quoted diffs (`> diff --git ...`, `> @@ ...`) from git-send-email
/ email reply workflows produce 0 hunks because the parser matches
patterns against raw lines containing `> ` quote prefixes. Closes#141.
## Solution
Strip the `> ` quote prefix before pattern matching in the parser. Store
`quote_width` on each hunk. In `highlight.lua`, offset all extmark
column positions by `qw` and expand `pw > 1` guards to `qw > 0 or pw >
1` for DiffsClear suppression. Clamp body prefix DiffsClear `end_col` to
the actual buffer line byte length for bare `>` lines (1-byte buffer
lines where `end_col = pw + qw` would exceed bounds and cause
`nvim_buf_set_extmark` to silently fail inside `pcall`).
15 new specs covering parser detection, stripping, false-positive
rejection, and highlight column offsets including the bare `>` clamp
edge case.
