Implemented automatic door opening

In my initial implementation, doors opened when a character approached them (using a sensor collider). But it looked creepy 😅 Imagine simply walking past the doors and having them open unexpectedly.

In the current implementation, I analyze navigation paths to determine if characters pass through the door, and open it when they approach.

Additionally, I added small visual feedback for wall placement, fine-tuned navigation, adjusted controls, made a few QoL improvements, and fixed a bunch of bugs.

This is for my WIP open source life simulation game made with Bevy under the working title Project Harmonia.