trae-cli command not found

### Setup Error and lack of instructions

In the README.md, there is some examples show how to use `trae-cli`, but I didn't see any instruction about `trae-cli` installation. I run `pip install trae-cli` and got
```
ERROR: Could not find a version that satisfies the requirement trae-cli (from versions: none)
ERROR: No matching distribution found for trae-cli
```

I run `uv sync` to successfully install all dependencies, but when I run `python trae_agent/cli.py`, it shows this error
```
Traceback (most recent call last):
File "/Users/tempest/Documents/AI/trae-agent/trae_agent/cli.py", line 12, in
import click
ModuleNotFoundError: No module named 'click
```

I want to know more about how to correctly setup this agent.
By the way, I read the implementation, it is so efficient, I am amazed at the elegance, simplicity, and effectiveness of the trae agent's design.

Start with README.md and the dependency setup used by uv sync, then inspect trae_agent/cli.py and its click import. Document the correct installation and launch steps, including how the required dependencies are installed, and verify that the documented command runs without the reported ModuleNotFoundError.

Written by the indexing model from the issue text.