Documentation fixes for git clone URL & setup instructions

[schwentker]

Found several documentation issues that could affect setup experience:

Critical issue:

• Git clone command uses placeholder URL that would prevent new devs from cloning:

git clone https://github.com/yourusername/google-adk-box-agent.git

Probably should be:

git clone https://github.com/box-community/google-adk-box-agent.git

Setup instruction issues:

• Installation steps have duplicate numbering (two steps labeled "1")
• Command order might be confusing: shows uv sync then uv lock (I think typically you'd lock first or just sync, no?)
• License section has placeholder text "[Include your license information here]" - prolly should be updated or removed

Minor formatting:

• Some inconsistent code block spacing in configuration section