[examples] Added shapes_mouse_trail

[Bala050814]

This example demonstrates a fundamental technique for creating a fading visual trail behind a moving object (the mouse cursor) by tracking and managing a fixed-size array of historical positions.

It effectively shows how to implement a basic fixed-length queue (or buffer) to store time-series data, and then visually render that history with progressive fading and size reduction.

Technical Details
Category: shapes

Complexity: [★☆☆☆] 1/4 (Very Simple)

Focus: Core game loop pattern for storing object history.

Key Functions Demonstrated:

GetMousePosition()

Array Shifting: Logic to drop the oldest position and insert the newest.

DrawCircleV() with Fade(): Applying index-based color and size changes to visualize age.

Uniqueness: This example is unique as no existing raylib example is dedicated solely to illustrating this specific "history/trail" visual effect.