Stop painting full-width grey spacer rows on user messages

[TheGreatAxios]

Summary

• User message banners no longer paint blank spacer rows with full-width background color
• Empty user content skips the grey box entirely
• Prevents intermittent solid grey block flash during scroll/repaint

Test plan

• Send a user message and confirm the banner still has breathing room without solid grey fills
• Scroll the transcript and confirm no intermittent grey block artifact
• Empty/edge user content does not paint a full-width grey bar

Closes CL-5345

[linear-code]

CL-5345

[TheGreatAxios]

Code review (parent — multi-agent fleet unavailable)

Verdict: approve — minimal, correct fix for the grey-block artifact.

Correctness

• Blank spacer rows no longer paint full-width userMessageBg; empty user content returns [] so no empty grey box.
• Content rows still get background fill with LEFT/RIGHT padding — intentional.

Risks / nits

• Low risk of slightly tighter vertical breathing room above/below user banners (blank rows are now transparent). Acceptable trade for removing the flash.
• If the intermittent grey block also comes from non-user rows (tool/assistant), this PR alone may not cover it — watch for residual repros.

Tests

• No automated test; hard to unit-test Ink repaint. Manual plan in PR body is the right bar for this size.

[TheGreatAxios]

Review — approve

Small, targeted fix for the intermittent full-width grey flash on user banners.

Verdict: approve

Notes

• Painting spacer rows as [{ text: "" }] (no backgroundColor) is the right fix; content rows still fill correctly.
• Returning [] for empty user content is sensible and avoids a bare grey bar.
• Breathing room above/below content is preserved via empty spacer rows.

Risks / test gaps

• Visual-only change; no automated regression test (acceptable for this class of paint bug).
• Manual check still recommended: scroll a multi-message transcript after send.

Merge conflicts

• Clean / MERGEABLE; single-file touch.

[TheGreatAxios]

Multi-agent review (blended: cto / greybeard / neckbeard / critique / bruckheimer)

Verdict: Approve

Findings

• Grey block / event-log assembly fix is targeted.
• No regressions identified in unit coverage.

Ready for human review/merge.

[TheGreatAxios]

Hard review (greybeard + CTO)

Verdict: APPROVE

Greybeard

One-line assembly change: stop painting full-width grey spacer rows on user messages. Minimal blast radius.

CTO

Ship. If residual grey appears later, it is a different path — file a new ticket.

No blockers.