Built-in parsers

OpenViking only routes resources to built-in parsers. Applications add resources through add_resource; parser registries are internal implementation details.

For the complete Accessor, Parser, Understanding, Connector, and asynchronous execution flow, see Resource ingestion routing.

Each built-in parser implements BaseParser and returns a ParseResult. New formats are added to the repository as built-in parsers and registered in openviking/parse/registry.py.