Fix #167: remove undefined 'tops' reference that aborted renumber() with wrap on

Commit e1056df refactored renumber() to place gutter numbers by measured
.codeline geometry but left the one-frame verification pass reading the
removed 'tops' array — a ReferenceError at line 80 that aborts renumber()
before any number is assigned, leaving the wrap-ON gutter with blank filler
rows. Read the placement from the already-computed rowIdx array instead.

Verified locally (CDP bounding-box probes, 6-line paste incl. one long
unbroken token that wraps mid-word): gutter number top vs .codeline top
diff <= 0.1px for every line at 1400x900 and 375x812, wrap ON and OFF.
Wrap OFF keeps the plain '1..N' text gutter with no .gutline spans.
No console or CSP violations.

internal/web/static/paste-lines.js

@@ -77,7 +77,7 @@
     // gutter pass that changes the code column width reflows it. Verify the
     // placement one frame later and re-run if any line's row moved (#167).
     var placed = {};
-    for (var q = 0; q < tops.length; q++) placed[q] = Math.round((tops[q] - bodyTop) / lh);
+    for (var q = 0; q < rowIdx.length; q++) placed[q] = rowIdx[q];
     requestAnimationFrame(function () {
       var moved = false;
       var tops2 = [];