dsh-bouncing-squares-example: Example Plugin Demonstrating Granular Settings Scope

This plugin visually demonstrates the behavioral differences among the `session`, `workspace`, and `global` setting scopes in DeepSeek Harness (DSH) through three bouncing squares. It showcases various control types and registration and reading patterns in code. Developers must first install the dependent plugin and enable it in Harness. By switching sessions within the same workspace or switching workspaces, users can verify the lifecycle of settings at different levels: session colors remain independent, workspace settings follow the workspace, and global settings remain unchanged. This example serves as a best-practice reference for understanding DSH architecture choices.