Lists · tree guides fall from the parent's chevron and run unbroken across rows (#2)

The chevron takes its indent as a margin, so no gap parts it from its guide column; the cursor's ring is an overlay, so the guides fill the row through its border.

tasks/github.md

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+# GitHub round, 2026-10-03
+
+- [x] G1 PR #1: build on Windows with `escape_args`; review, verify, merge, answer CodeRabbit
+- [x] G2 Issue #2: tree guides line up under the chevron and run unbroken across rows
+- [ ] G3 Issue #3: Checkbox, Switch, Radio, Slider and Select name their role, label and state
+- [ ] G4 Push, comment on #2 and #3, close #2