This PR adds support for the eval to read environment variables from a
`.env` file located in the `crates/eval` directory.
For instance, you can use it to set your Anthropic API key:
```
ANTHROPIC_API_KEY=<secret>
```
Release Notes:
- N/A
This update generates a single self-contained .html file that shows an
overview of evaluation threads in the browser. It's useful for:
- Quickly reviewing results
- Sharing evaluation runs
- Debugging
- Comparing models (TBD)
Features:
- Export thread JSON from the UI
- Keyboard navigation (j/k or Ctrl + ←/→)
- Toggle between compact and full views
Generating the overview:
- `cargo run -p eval` will write this file in the run dir's root.
- Or you can call `cargo run -p eval --bin explorer` to generate it
without running evals.
Screenshot:

Release Notes:
- N/A
Also, we moved the logic for driving the agentic loop into `Thread` so
that we don't have to re-implement it.
Release Notes:
- N/A
---------
Co-authored-by: Nathan Sobo <nathan@zed.dev>