fix(web): stop clipping the bottoms of diff file names

[shivamhwp]

File names in diff headers had the bottoms of g, p, j and y cut off.

Pierre clips file names with overflow: hidden for its start ellipsis, and our line-height: 1 made that box 12px tall. Now only the name gets a 16px line, so the header stays 32px (diffHeaderHeight). The name's hover underline was always clipped, so it's removed to keep hover looking the same as before.

Same bug as #8912 (thanks @gshahbazian), without growing the header to 35px.

Done by Claude Opus 5.5 in Claude Code.

🤖 Generated with Claude Code

[github-actions]

Thread transfer impact

✅ Thread transfer remains within every enforced ceiling.

ℹ️ The exact PR base did not have a successful artifact. Baseline uses the latest successful main measurement shown below.

Provider	Metric	Main baseline	This PR	Impact	PR ceiling
Codex	Total thread wire	13.5 KiB	13.5 KiB	−1 B (−0.0%)	15.1 KiB	✅
Codex	Thread snapshot wire	7.0 KiB	7.1 KiB	+15 B (+0.2%)	7.3 KiB	✅
Codex	Live turn WebSocket wire	6.5 KiB	6.4 KiB	−16 B (−0.2%)	7.8 KiB	✅
Codex	Live turn WebSocket decoded	56.3 KiB	56.2 KiB	−44 B (−0.1%)	66.4 KiB	✅
Codex	Live turn messages	10	9	−1 (−10.0%)	21	✅
Claude	Total thread wire	13.5 KiB	13.5 KiB	−12 B (−0.1%)	15.1 KiB	✅
Claude	Thread snapshot wire	7.1 KiB	7.1 KiB	+5 B (+0.1%)	7.3 KiB	✅
Claude	Live turn WebSocket wire	6.5 KiB	6.4 KiB	−17 B (−0.3%)	7.8 KiB	✅
Claude	Live turn WebSocket decoded	57.0 KiB	57.0 KiB	0 B (0.0%)	66.4 KiB	✅
Claude	Live turn messages	9	9	0 (0.0%)	21	✅

Baseline: 408ff8a · PR result: 8eef750 · 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: 114.0 KiB
• Claude decoded thread snapshot: 114.7 KiB

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

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ℹ️ Recent review info

⚙️ Run configuration

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Plan: Advanced

Run ID: 6c37a197-5aed-4ee0-8ae7-4574a1072c5a

📥 Commits

Reviewing files that changed from the base of the PR and between 9f07e2a and 8eef750.

📒 Files selected for processing (1)

• apps/web/src/components/diffs/StyledDiffCodeView.tsx

🚧 Files skipped from review as they are similar to previous changes (1)

• apps/web/src/components/diffs/StyledDiffCodeView.tsx

Included review availability: This review used your included allowance. Your plan provides up to 10 included reviews per hour; 8 remain after this review.

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📝 Walkthrough

Walkthrough

The diff header title and previous-name elements now use a 16px line height. The title no longer has an underline or an underline-color transition. Its hover color remains unchanged.

Changes

Diff header styling

Layer / File(s)	Summary
Update diff header title styling apps/web/src/components/diffs/StyledDiffCodeView.tsx	The title and previous-name elements use a 16px line height. The title transition applies only to text color, and the hover color remains unchanged.

Priority: ⬇️ Low

Estimated code review effort: 1 (Trivial) | ~3 minutes

Change: Bug fix

Merge Risk: ⚪ Minimal · up to 8eef7

The styling change addresses filename clipping without an established layout or interaction regression. No actionable merge-blocking risk remains.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check. Docstring coverage is scoped to functions touched by this diff. Analyzed 0 functions across 1…
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Title check	✅ Passed	The title clearly identifies the web bug fix: preventing diff file names from being clipped. It is concise and specific.
Description check	✅ Passed	The description explains the problem, the cause, the CSS change, and the constraint that the header remains 32px tall. It includes before-and-after UI evidence. It does not use the template headings o…

✨ Finishing Touches

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[macroscopeapp]

Approvability

Verdict: Approved at 8eef750

Macroscope's review found this PR approvable — This is a focused one-file CSS fix for clipped diff filenames, preserving the existing header height and changing no data or application workflows. The accompanying hover-style adjustment is minor and localized to the diff viewer.

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Dismissing prior approval to re-evaluate 8eef750