Add zoom sound effect

[wannerdev]

Description

Adds audio feedback when players zoom in or out using mouse wheel or pinch-to-zoom gestures.

Changes

• Added SolarSystemAssets import to gameplay module
• Implemented zoom sound playback in camera_zoom function (mouse wheel)
• Added zoom sound to camera_pinch_zoom function (mobile pinch-to-zoom)
• Sound plays only when zoom level actually changes (prevents spam)
• Works for both desktop (mouse wheel) and mobile (pinch gesture)
• Using warning_sound as placeholder (can be replaced with custom zoom sound)
• Added level change detection to prevent unnecessary sound playback

Sound Behavior

• Mouse Wheel: Sound plays when scrolling changes zoom level
• Pinch Zoom: Sound plays when pinch gesture changes zoom level
• No Spam: Only plays when level actually changes (not on every scroll event)
• Threshold: Pinch zoom has 5.0 pixel threshold to avoid jitter sounds
• Stepped Zoom: Works with existing 5-level zoom system

Zoom Levels

The game has 5 predefined zoom levels:

1. 0.1 (most zoomed out)
2. 0.15
3. 0.25 (default)
4. 0.5
5. 0.75 (most zoomed in)

Benefits

• Provides immediate audio feedback for zoom actions
• Helps players understand zoom is working
• Enhances game feel and responsiveness
• Works on both desktop and mobile
• Prevents audio spam with level change detection
• Makes zoom mechanic more discoverable

Technical Details

• Stores old zoom level before processing input
• Compares old vs new level after input
• Only spawns audio entity if levels differ
• Uses PlaybackSettings::DESPAWN for automatic cleanup
• Integrated into existing zoom systems
• No performance impact (sound only on level change)

Audio Asset

• Currently using warning_sound (beepx3.wav) as placeholder
• Can be easily replaced with custom zoom sound:
  • Short "whoosh" or "click" sound recommended
  • Should be subtle and not distracting
  • Duration: 0.1-0.3 seconds ideal

Testing

• Use mouse wheel to zoom in/out and verify sound plays
• Use pinch gesture on mobile and verify sound plays
• Scroll rapidly and verify sound doesn't spam
• Check that sound only plays when zoom level changes
• Verify works at all zoom levels (1-5)
• Test that pinch threshold prevents jitter sounds

Related Issue

Fixes: Sound Effects - Add zoom sound effect