Validate data schema for file/input/output

Validate schema for data when loading from file or input parameter or output parameter.

Not exhaustive list:
- [ ] compiled grammar file (.agr.json)
- [ ] compiled action schema file (.pas.json)
- [ ] display log
- [ ] etc.

Start by locating the code paths that load files and accept input or output parameters; the issue does not name specific files or tests. Review how compiled grammar files (.agr.json), compiled action schema files (.pas.json), and the display log are currently handled. Done means schema validation covers the listed data sources and its expected behavior is verified.

Written by the indexing model from the issue text.