Stylus input bug: fast handwriting produces incorrect lines (trajectory ignored)

When using a stylus for fast handwriting, the lines are rendered incorrectly: the line is shortened and connects only the start and end points, ignoring the actual trajectory of the pen. This makes normal handwriting impossible on the whiteboard.

Steps to reproduce:

1. Open whiteboard.
2. Select the pen/drawing tool for stylus input.
3. Write quickly with the stylus on the canvas.

Expected behavior:
The line should follow the real path of the pen regardless of speed.

Actual behavior:
The line is shortened and goes straight from start to finish, not following the pen's path.

Environment:

• Chrome for Android version: 141.0.7390122
• Nextcloud version: 32.0.1
• Nextcloud Whiteboard version: 1.4.0

Screenshot:

This issue is critical for tablet and stylus/pen users.

Start by reproducing the issue in the whiteboard with Chrome for Android 141 and a stylus using the pen/drawing tool. Trace the input handling and line rendering path to determine where fast handwriting loses intermediate trajectory points. Done means fast stylus strokes follow the real pen path rather than connecting only their start and end points.