Compiler mode: Return all errors + partial parsed block

For IDE integration, we need to make the block parser find all the errors in a block file and also return whatever parsed block information that it could.

Start by locating the block parser entry point used for IDE integration. Determine how parsing currently reports errors and parsed block information, then define tests for collecting all block errors while preserving any successfully parsed data. Done means the parser exposes both results for a block containing multiple errors.

Written by the indexing model from the issue text.