Shell · ColumnShell: columns to the window's top, each under a header that drags it; the traffic lights or controls in the first or last (#6)

tasks/github.md

@@ -9,6 +9,6 @@
 # GitHub round, 2026-10-05
 
 - [x] G6 Issue #7: an IME composition restarts the caret's blink, as every edit does; its ranges are logged; tested
-- [ ] G7 Issue #6: `layout::SidebarShell`, a sidebar that runs to the window's top with the traffic lights, beside one or two panes that bring their own headers; tested
+- [x] G7 Issue #6: `shell::ColumnShell`, a sidebar that runs to the window's top with the traffic lights, beside one or two panes that bring their own headers; tested
 - [ ] G8 Issue #6: a Layout story, `stories.json`, AGENTS.md and the PRD line; the story runs live on the site
 - [ ] G9 Push, deploy, reply on #6 and #7, close #6

tasks/reviews.md

@@ -383,3 +383,6 @@
 | L4 | 1 | PASS | |
 | L5 | 1 | PASS | |
 | G6 | 1 | PASS | codex gpt-6.1-sol high |
+| G7 | 1 | FAIL | at 280px a 200px sidebar left the Windows close button past the shell |
+| G7 | 2 | FAIL | Edit and Share beside the Windows buttons still pushed the close button to 322px |
+| G7 | 3 | FAIL | the host's items shrank to 0px, out of reach; fixed after the cap (one control's width at least, a wheel test), not reviewed again |