fix(ui): space work-log rows by the column gap alone

[Astro-Han]

Summary

Rows in an expanded work log were not evenly spaced: 16px above every reasoning and tool row, but 8px above intermediate text. Each text line therefore read as attached to the row above it.

Root cause: Astryx ChatReasoning and ChatToolCalls carry an intrinsic margin-block-start: var(--spacing-2). That default fits Astryx's own ChatMessage composition (4px children gap, ghost bubbles with 12px block padding). Maka's .maka-processing-body is a flex column with its own 8px gap and a flush assistant bubble, so the component margin stacked on the gap.

Fix: the processing body zeroes its children's block-start margin, making gap the only spacing between rows. The existing first-child rule that spaces the body from its summary is unchanged (still 8px). timeline-fold.ts only lets text and processing entries reach .maka-assistant-answer-content, so reasoning and tool rows never sit directly in that column and it needs no rule.

Alternatives not taken: Astryx's xstyle seam needs a StyleX compile step Maka does not have; dropping the atom from the ejected ChatReasoning would fix only reasoning rows and fork the copy from upstream.

Verification

• NativeConversation story play opens the multi-step turn's work log and asserts every adjacent row gap equals the body's row-gap. Built Storybook with the CSS rule disabled: the play fails (message-bubble → tool-calls: 16, tool-calls → reasoning: 16). With the fix it passes in light and dark through smokeStory from scripts/storybook-visual-smoke.mjs (play, console, AX audit).
• Measured gaps, main → branch: reasoning→text 8 → 8, text→tool 16 → 8, tool→reasoning 16 → 8.
• npm --workspace @maka/desktop run typecheck:stories, npm --workspace @maka/ui run build, npm run format, npm run lint: pass.
• Not run locally: full smoke and E2E (left to CI).

Same story, same 1280px viewport; BEFORE from main's storybook-static, AFTER from this branch's.

AI use

Select exactly one:

• No generative tool made a substantive contribution
• Generative tooling made a substantive contribution

Tool(s) and scope: Claude Code diagnosed the spacing, wrote the CSS fix and story assertion, and produced the comparison images.

Checklist

• Tests cover the change and fail without it
• Lint, format, typecheck and the affected suites pass locally

Does this PR entail a change in behavior?

• Yes — described under Summary above
• No

[jackwener]

I reviewed 45b4ee6e3b7c918b4f0fb9a0d676eaf14366da71.

No P0–P2.

Astryx ChatReasoning and ChatToolCalls bring margin-block-start, which stacked on .maka-processing-body's 8px gap. Zeroing that margin on the body's children leaves gap as the only space between rows. The first-child rule still spaces the body from the summary.

Hosted test was still running at this review.

简体中文

我审查了 45b4ee6e3b7c918b4f0fb9a0d676eaf14366da71。没有 P0–P2。

过程记录里 Astryx 行自带上边距，叠在 8px gap 上。把子项 margin-block-start 清掉后只剩 gap。本审查时 hosted test 仍在跑。

---

Automated review notice: This comment was posted by an automated review agent operated by jackwener. It is not an independent human review and does not replace one.