feat: Direct Client API - Add Delete Agent functionality

[jason51553262]

Risks

Low

Background

For my use case, I'm building a web app that can start and stop agents with characters configured in a UI. For this application it's not practical to restart the Eliza Docker Service each time a new agent is added or removed as this will offline existing active agents.
The existing Direct Client API has a POST /agents/:agentId/set endpoint which can be used to either create or update an agent with a character JSON passed into the request body. It makes sense to also implement Delete.

What does this PR do?

Adds the following APIs to Direct Client:

• DELETE /agents/:agentId (Stops agent clients and unregisters the agent)

I've also added support for an environment variable PREVENT_UNHANDLED_EXIT which when set, will handle both uncaughtException and unhandledRejection and send the exception to console.error instead of allowing the process to terminate.

What kind of change is this?

Improvements (to existing Direct Client API functionality)

Why are we doing this? Any context or related work?

So that an integrated application can start and stop agents without requiring a restart of Eliza

Documentation changes needed?

My changes require a change to the project documentation.

Testing

Where should a reviewer start?

Only one change in api.ts

Detailed testing steps

Execute the follow REST calls in Postman:

(Create and Update)
POST http://localhost:3000/agents/:agentId/set { character }

(Delete)
DELETE http://localhost:3000/agents/:agentId

In the character file use a client with a required secret such as telegram and TELEGRAM_BOT_TOKEN.
Test with a valid TELEGRAM_BOT_TOKEN and also test without the TELEGRAM_BOT_TOKEN at all.
In the current build, when you POST /agents/:agentId/set with a telegram client but a missing TELEGRAM_BOT_TOKEN, a validation error will be thrown and the system will exit as the existing code that calls startAgent is not catching this error. Fixing in this PR.

[github-actions]

Hi @jseparovic! Welcome to the elizaOS community. Thanks for submitting your first pull request; your efforts are helping us accelerate towards AGI. We'll review it shortly. You are now an elizaOS contributor!

[wtfsayo]

lgtm