Client: Handle PlantBombCommand

[fnpratto]

Description:
Handle player input for planting the bomb, send request to server, and render progress/animation/UI effects.

Tasks:

• Detect bomb plant key press (e.g. 'E') when inside bomb zone.
• Render bomb planting animation (progress bar or hand animation).
• Show bomb planted notification if server confirms.
• Start and display countdown timer on HUD.
• Grey out plant UI if not in bomb zone or no bomb held.