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https://microsoft.github.io/autogen/docs/Contribute before opening a
pull request. -->

This PR has 3 main improvements. 

- Token streaming 
- Adds support for environment variables in the app settings 
- Updates AGS to persist Gallery entry in db.

## Adds Token Streaming in AGS.  

Agentchat now supports streaming of tokens via
`ModelClientStreamingChunkEvent `. This PR is to track progress on
supporting that in the AutoGen Studio UI.

If `model_client_stream` is enabled in an assitant agent, then token
will be streamed in UI.

```python
streaming_assistant = AssistantAgent(
    name="assistant",
    model_client=model_client,
    system_message="You are a helpful assistant.",
    model_client_stream=True,  # Enable streaming tokens.
)

```

https://github.com/user-attachments/assets/74d43d78-6359-40c3-a78e-c84dcb5e02a1


## Env Variables 
Also adds support for env variables in AGS Settings

You can set env variables that are loaded just before a team is run.
Handy to set variable to be used by tools etc.

<img width="1291" alt="image"
src="https://github.com/user-attachments/assets/437b9d90-ccee-42f7-be5d-94ab191afd67"
/>


> Note: the set variables are available to the server process.

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## Why are these changes needed?

<!-- Please give a short summary of the change and the problem this
solves. -->

## Related issue number

<!-- For example: "Closes #1234" -->
Closes #5627  
Closes #5662 
Closes #5619 

## Checks

- [ ] I've included any doc changes needed for
<https://microsoft.github.io/autogen/>. See
<https://github.com/microsoft/autogen/blob/main/CONTRIBUTING.md> to
build and test documentation locally.
- [ ] I've added tests (if relevant) corresponding to the changes
introduced in this PR.
- [ ] I've made sure all auto checks have passed.

This PR does the following: 

- Fix warning messages in AGS on launch.
- Improve Cli message to include app URL on startup from command line
- Minor improvements default gallery generator. (add more default tools)
- Improve new session behaviour.



## Related issue number

Closes #5097

## Checks

* fix import issue related to agentchat update #4245

* update uv lock file

* fix db auto_upgrade logic issue.

* im prove msg rendering issue

* Support termination condition combination. Closes #4325

* fix db instantiation bug

* update yarn.lock, closes #4260 #4262

* remove deps for now with vulnerabilities found by dependabot #4262

* update db tests

* add ability to load sessions from db ..

* format updates, add format checks to ags

* format check fixes

* linting and ruff check fixes

* make tests for ags non-parrallel to avoid db race conditions.

* format updates

* fix concurrency issue

* minor ui tweaks, move run start to websocket

* lint fixes

* update uv.lock

* Update python/packages/autogen-studio/autogenstudio/datamodel/types.py

Co-authored-by: Eric Zhu <ekzhu@users.noreply.github.com>

* Update python/packages/autogen-studio/autogenstudio/teammanager.py

Co-authored-by: Eric Zhu <ekzhu@users.noreply.github.com>

* reuse user proxy from agentchat

* ui tweaks

---------

Co-authored-by: Eric Zhu <ekzhu@users.noreply.github.com>
Co-authored-by: Hussein Mozannar <hmozannar@microsoft.com>

* add skeleton worflow manager

* add test notebook

* update test nb

* add sample team spec

* refactor requirements to agentchat and ext

* add base provider to return agentchat agents from json spec

* initial api refactor, update dbmanager

* api refactor

* refactor tests

* ags api tutorial update

* ui refactor

* general refactor

* minor refactor updates

* backend api refaactor

* ui refactor and update

* implement v1 for streaming connection with ui updates

* backend refactor

* ui refactor

* minor ui tweak

* minor refactor and tweaks

* general refactor

* update tests

* sync uv.lock with main

* uv lock update