QA FAIL of PR #179 (verified on palette-dev 2026-09-10) found two defects:
1) Row accounting: splitLines() joined .codeline blocks with '\n' text
nodes. Since dee062d made .codeline display:block, each interleaved
newline text node rendered as its own extra visual row in the code
column under pre-wrap, but renumber() counted only .codeline span
heights, so the gutter had one fewer row per line break and numbers
drifted off alignment on wrapped lines. Fix: join('') so blocks are
adjacent with no phantom newline rows; blank source lines become
empty blocks given a line box via .codeline:empty::before (ZWJ) in
app.css so they still count as one row.
2) Inline gutter spans: .gutline spans were appended with no separators
and .code .gutter .gutline { display: block } did not exist on the
deployed build, so all numbers landed on one row. That rule is
present in origin/dev (merged via #183); kept unchanged and verified
by rendering in a local build.
Wrap OFF path unchanged: gutter still gets '1\n2\n3\n4' text and the
horizontal-scroll gutter behavior is untouched (no CSS changes to
scrolling; only a :empty line-box rule). CSP unchanged: no inline
styles/handlers, static JS only.
fen