chore(model): add user agent request header to model request (#199)

* chore(model): add user agent request header to model request

* add installation method to README.md

Author: yaozheng-fang

README.md

@@ -15,6 +15,17 @@ A [tutorial](https://github.com/volcengine/veadk-python/blob/main/veadk_tutorial
 
 ## Installation
 
+### From PyPI
+
+```python
+pip install veadk-python
+
+# install extensions
+pip install veadk-python[extensions]
+```
+
+### Build from source
+
 We use `uv` to build this project ([how-to-install-uv](https://docs.astral.sh/uv/getting-started/installation/)).
 
 ```bash

veadk/consts.py

@@ -27,6 +27,7 @@
         "x-is-encrypted": getenv("MODEL_AGENT_ENCRYPTED", "true"),
         "veadk-source": "veadk",
         "veadk-version": VERSION,
+        "User-Agent": f"VeADK/{VERSION}",
     },
     "extra_body": {
         "caching": {