Fix: Improve JTabbedPane tab title rendering

[poce1don]

This PR improves the rendering of tab titles in JTabbedPane, specifically when tabs are placed vertically (Left/Right). Previously, rotated text often exhibited minor visual distortions and aliasing issues. Vertical text rendering is now much closer in quality to horizontal rendering, providing a more professional and consistent UI look across all tab placements

Scale 125%

Scale 150%

Vector-based Rendering: For rotated text, the implementation now uses TextLayout.getOutline() to render the title as a Shape. This ensures high-quality vector-based rendering, eliminating the "blurred" or "jagged" look that sometimes occurred with standard string drawing during rotation.

Horizontal Rendering: Kept the original drawStringUnderlineCharAt for horizontal tabs to maintain peak performance and native font rendering consistency.

Mnemonic Support: Manually implemented the underline logic for vertical text using TextHitInfo, ensuring the mnemonic remains perfectly aligned with the vector-based title.

Important Notes:
This improvement applies only to plain text titles. For tabs using HTML content, the original View.paint() logic is preserved, and the rendering remains unchanged.