[Daytona] executeCommand improvements (extension)

[AleksandarCole]

1. Support background/detached execution -- Currently the command must complete within the timeout to be considered successful. For starting long-running services (like a web server), the command blocks forever. A background: true or detach: true option that returns success once the command starts (or after a healthcheck) would be very useful.

2. Longer default timeout -- The default 60-second timeout is too short for common operations like go build (2-5 min), npm install (1-3 min), or pulling Docker images. Consider raising the default to 300s or making it more prominent in the UI.

3. Working directory default -- When chaining multiple commands on the same sandbox, having to repeat the cwd is tedious. Consider defaulting to the last-used working directory or allowing it to be set at sandbox level.