fix(launcher): use grid cell height for list result rows

[TotalyEnglizLitrate]

Summary

Bind each result row to the tile's actual height instead of recomputing the row height independently, keeping row sizing consistent with the grid cell height.

Motivation

List rows recomputed their own height independently of the grid cell height, and resized late after launch leaving selection/hover highlight boxes mismatched with the actual row bounds. Binding each row to the tile's actual height keeps sizing consistent, avoiding the post-launch resize and fixes the highlight boxes.

Type of Change

• Bug fix
• New feature
• Breaking change
• Refactoring
• Build / packaging

Related Issue

Closes #3285

Testing

opened launcher to verify no post-launch resize and no overlap between selection/hover highlights

Manual Coverage

• Tested on Niri
• Tested on Hyprland
• Tested on Sway
• Tested on another compositor:
• Tested with different bar positions and density settings
• Tested at different interface scaling values
• Tested with multiple monitors

Screenshots / Videos

2026-07-06_20-20-59.mp4

Checklist

• This PR is ready for review, or it is marked as Draft.
• I read and followed the relevant guidance in CONTRIBUTING.md.
• I ran just format with clang-format v22+ installed, or this PR has no code changes.
• I ran the relevant build or test commands, or explained why they were not run.
• I self-reviewed the changes.
• I checked for new warnings or errors.
• I will update end-user documentation after merge, or this PR does not change user-facing configuration or behavior.
• I added or updated assets/translations/en.json, or this PR adds no new user-facing strings.
• I did not edit non-English translation files unless this PR is explicitly for translation tooling, an import/export sync, or a maintainer-requested locale change.
• I used the existing canonical names for config keys, IPC names, paths, and identifiers.

Additional Notes

N/A

[Ly-sec]

Hey @TotalyEnglizLitrate , that looks good to me. I'll merge it, thank you very much.