fix(ui): use tabStyle for inactive tabs to resolve unused var lint error

[fullstackjam]

Summary

• tabStyle was declared in selector_view.go but never used, causing golangci-lint to fail
• renderTabBar() was creating an inline neighborStyle (same #666 colour) instead of using the package-level var
• Replace the inline local with tabStyle to remove the duplication and satisfy the linter

Test plan

• go vet ./internal/ui/... passes
• Lint CI job passes

[github-actions]

👋 Thanks for opening this pull request!

Before merging:

• Code follows existing patterns in the codebase
• go build ./... and go vet ./... pass
• Commit message is clear and descriptive

@fullstackjam will review this soon. Thanks for contributing! 🚀

[codecov]

Codecov Report

❌ Patch coverage is 0% with 2 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
internal/ui/selector_view.go	0.00%	2 Missing ⚠️

📢 Thoughts on this report? Let us know!