fix(planreview): dock the comment box under the plan, and stop it stealing scroll

[tusharbhardwaj-bk]

Four reported problems with the comment composer, three of them one root cause.

Scroll jumped to the top when the box opened

useSelectionAnchor returned before computing anything when frozen was set:

useEffect(() => {
  if (frozen) return;          // ← never subscribes, never syncs
  ...
}, [frozen, syncToSelection]);

The composer passed frozen: true, so its anchor was permanently null and it always took the fallback branch — position: absolute; bottom: 1rem inside the scrolling document — and then autofocused itself, which scrolled the plan to wherever that had landed. From the bottom of a long plan that reads as a jump to the top.

The frozen branch was mine, from the previous PR, and never worked. It and the option are removed; the toolbar simply doesn't render while the composer is open.

The box was too small, and now it docks

Per the request, the composer goes back to being docked under the plan rather than floating over it. That also fixes the scroll problem structurally: it is a sibling of the scroll container, not a child, so focusing it cannot move the plan. focus({ preventScroll: true }) is a second guard.

It starts at five lines and grows with what is typed, capped at 30vh so it can never swallow the plan it is about. Measured in JS rather than CSS field-sizing, which Safari and Firefox still lack.

"Approve with comments" was cut in half

Two buttons sharing a row in a 288px rail. They stack now, so no label truncates at any panel width.

Verification

155 tests passed across 11 scoped files; tsgo --noEmit clean for apps/web; lint and check-fork-markers.ts pass.

New tests pin the two properties that were asked for and could silently regress: the composer's root element carries no absolute/fixed/sticky positioning, and it renders min-height:6rem / max-height:30vh. Both assert against the root element's own classes — a whole-markup search would match the before:absolute and disabled: utilities every button carries, and pass for the wrong reason.

Reviewer check: scroll to the bottom of a long plan, select a line, hit Comment — the plan should not move, and the box should grow as you type and then stop at a third of the window.

🤖 Generated with Claude Code

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[github-actions]

Thread transfer impact

✅ Thread transfer remains within every enforced ceiling.

ℹ️ No successful main baseline artifact is available yet. This run establishes the initial measurement.

Provider	Metric	Main baseline	This PR	Impact	PR ceiling
Codex	Total thread wire	—	11.4 KiB	—	15.1 KiB	✅
Codex	Thread snapshot wire	—	5.7 KiB	—	7.3 KiB	✅
Codex	Live turn WebSocket wire	—	5.7 KiB	—	7.8 KiB	✅
Codex	Live turn WebSocket decoded	—	50.3 KiB	—	66.4 KiB	✅
Codex	Live turn messages	—	10	—	21	✅
Claude	Total thread wire	—	11.4 KiB	—	15.1 KiB	✅
Claude	Thread snapshot wire	—	5.7 KiB	—	7.3 KiB	✅
Claude	Live turn WebSocket wire	—	5.7 KiB	—	7.8 KiB	✅
Claude	Live turn WebSocket decoded	—	51.2 KiB	—	66.4 KiB	✅
Claude	Live turn messages	—	11	—	21	✅

Baseline: unavailable · PR result: 02c858a · Source CI: success

Scenario and decoded snapshot size

10 historical turns, 5 command tools per turn, 878.9 KiB retained MCP result per historical turn, and a 1.05 MiB retained result in the measured turn.

• Codex decoded thread snapshot: 95.6 KiB
• Claude decoded thread snapshot: 96.3 KiB

Updated in place by a trusted workflow. PR artifacts are strictly validated and never executed.