Also updates CI to always run this - that way we ensure that disabling
or enabling tests does not become stale at some point and thus can
safely add this.
Release Notes:
- N/A
- [GPUI] N/A
Move shell command parsing logic (`extract_commands` and supporting
code) from the agent crate into a new `shell_command_parser` crate so it
can be reused by `agent_servers` for ACP permission checking.
Release Notes:
- N/A
Finn Evers