Puzzle tooltips: side-to-move and objective

[jasonappah]

Description
Add contextual tooltips to the puzzle UI that always display the side to move and the objective sourced from puzzle metadata (e.g., “White to mate in 2”).

Why

• Reduce confusion for users starting puzzles
• Align on terminology and show consistent guidance

Scope

• Render tooltip content from puzzle data
• Ensure tooltip updates when puzzle changes or flips
• Handle localization-ready string formatting

Acceptance

• Tooltip visible on puzzle start with correct side and objective
• Updates correctly after reset or new puzzle
• Works in simulator and standard UI themes