This PR changes agents desktop resolution from 1366x768 to 1920x1080.
Anthropic requires the that the resolution of desktop screenshots fits
in 1,150,000 total pixels, so we downscale screenshots to 1280x720
before sending them to the LLM provider.
Resolution scaling was already implemented, but our code didn't exercise
it. The resolution bump showed that there were some bugs in the scaling
logic - this PR fixes these bugs too.
Implement the backend for the desktop feature for agents.
- Adds a new `/api/experimental/chats/$id/desktop` endpoint to coderd
which exposes a VNC stream from a
[portabledesktop](https://github.com/coder/portabledesktop) process
running inside the workspace
- Adds a new `spawn_computer_use_agent` tool to chatd, which spawns a
subagent that has access to the `computer` tool which lets it interact
with the `portabledesktop` process running inside the workspace
- Adds the plumbing to make the above possible
There's a follow up frontend PR here:
https://github.com/coder/coder/pull/23006
Hugo Dutka