Fix keyboard hint labels on wrapped and scrolled content

[raphamorim]

Follow-up to #1884, porting the keyboard hint mode (the labeled-jump flow) onto the same logical-line matching the hover path now uses.

The label finder had the same two defects the hover path had, plus one of its own: it searched one visual row at a time, so soft-wrapped URLs matched truncated or produced no label; byte-versus-cell drift shifted label anchors right of the match when multi-byte characters preceded it; and it skipped any line with a negative grid index, so hint mode showed no labels at all for scrollback content while the view was scrolled.

find_regex_matches now walks the viewport one logical line at a time, in grid coordinates, so scrolled views resolve. Each anchor extracts the unwrapped line with the byte-to-cell map and collects all matches through LogicalLine::matches, which the hover path's match_at is now a filter over, so both paths share one implementation, including tail post-processing, the per-search retry budget, and wide-character end extension. Wrap chains longer than the scan bound are re-anchored in tiles; overlapping tiles can produce a duplicate match, which the existing sort plus dedup in update_matches collapses.

New tests cover a soft-wrapped URL yielding a single match with cell-exact bounds spanning both rows, and label alignment with multi-byte prefixes.