fix(opencode): command palette mouse hover highlights wrong item

[kitlangton]

fix.mp4

Summary

• align hover selection index with grouped command list ordering
• keep mouse hover consistent after filtering

Verification

• open command palette (Ctrl+P) and hover items
• optionally type a filter (e.g. press "e" a few times) and hover again

Fixes #7722

[github-actions]

Hey! Your PR title Fix command palette hover index doesn't follow conventional commit format.

Please update it to start with one of:

• feat: or feat(scope): new feature
• fix: or fix(scope): bug fix
• docs: or docs(scope): documentation changes
• chore: or chore(scope): maintenance tasks
• refactor: or refactor(scope): code refactoring
• test: or test(scope): adding or updating tests

Where scope is the package name (e.g., app, desktop, opencode).

See CONTRIBUTING.md for details.

[github-actions]

The following comment was made by an LLM, it may be inaccurate:

No duplicate PRs found

[github-actions]

Thanks for your contribution!

This PR doesn't have a linked issue. All PRs must reference an existing issue.

Please:

1. Open an issue describing the bug/feature (if one doesn't exist)
2. Add Fixes #<number> or Closes #<number> to this PR description

See CONTRIBUTING.md for details.