fromString
Parses the raw op value from the pw_live JSON into an operation.
The backend emits protojson enum names with the OPERATION_ prefix ("OPERATION_START" / "OPERATION_UPDATE" / "OPERATION_END"); matching is exact, against the full names only. Anything else (short forms, garbage, null) yields null and the push is consumed without rendering.
Return
the matching operation, or null if raw is null or unrecognized
Parameters
raw
the raw op value from the payload (e.g. "OPERATION_START")