## What changed
- Add `environmentConfigRead` to exec-server environment capabilities and advertise it for local executors.
- Default the capability to `false` when deserializing responses from older executors.
## Testing
- Verify legacy capability responses remain compatible and the environment config integration reports support.
GitOrigin-RevId: c2110fea9e0e6e756eaeaaad096c50a943668c99
## What changed
- Add the `environmentConfig/read` RPC for selecting literal TOML paths from executor-local config and requirements layers.
- Return layer precedence, cloud insertion points, source and base-directory metadata, and executor home and hostname context without normalizing path-bearing values.
- Expose the operation through both remote clients and local `Environment` instances, with invalid selectors reported as invalid parameters.
## Testing
- Cover projected remote config reads and rejection of empty selectors.
GitOrigin-RevId: fee15bf833de6bcb2058d405ed5b1d5d928d7218
