fix(presets): center list editor row content and button within the row card

[Transmigration-zhou]

Problem

Follow-up to #1094. Two remaining alignment defects in the list editor row cards (reported downstream in KGM-4586):

1. When a row's content is shorter than the 48px delete button (e.g. a single compact input), the flex row's height is driven by the button, the content column stretches to that height (default align-items: stretch) and sticks to its top — the button sits (48 − content)/2 px below the input's centerline.
2. The card's pt-4 pb-0 padding relied on the row content ending with a v-input details placeholder to supply the bottom gap. Content without one (hide-details inputs, plain components) gets pinned against the card's bottom border, visibly off the card's vertical centerline.

Fix

• align-self-center on the content column: a short content block centers against the button instead of stretching; rows taller than the button define the row height themselves and are unaffected.
• pa-4 on the row card: symmetric vertical padding, so the card's spacing no longer depends on the content's internal structure. Rows whose content ends with a details placeholder gain 16px of bottom padding (16/36 total) — slightly roomier, but the card no longer collapses onto content that doesn't carry one.

Testing

• go test ./presets/... passes.
• Verified in the kakuyasu seller portal via a local go.mod replace: with hide-details inputs, both a single-input row and a two-field row measure a 0.0px offset between the delete button center and the card centerline.

🤖 Generated with Claude Code

[deepsource-io]

DeepSource Code Review

We reviewed changes in b896822...2b69640 on this pull request. Below is the summary for the review, and you can see the individual issues we found as inline review comments.

See full review on DeepSource ↗

PR Report Card

Overall Grade

Security   Reliability   Complexity   Hygiene

Code Review Summary

Analyzer	Status	Updated (UTC)	Details
Go		Jul 7, 2026 3:43a.m.	Review ↗

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

Files with missing lines	Coverage Δ
presets/listeditor.go	78.08% <100.00%> (ø)

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[Transmigration-zhou]

Superseded by #1096 — same goal (center the delete button), but strictly scoped to the button via absolute positioning against the card; row content layout stays byte-for-byte unchanged, unlike the padding change here.