Add AsyncAPI and JSON Schema docs endpoints and builders

[cobycloud]

Motivation

• Provide additional system documentation formats (AsyncAPI and JSON Schema) alongside existing OpenAPI/OpenRPC tooling so services can expose messaging and schema artifacts.

Description

• Added asyncapi.py and jsonschema.py under system/docs to build and mount AsyncAPI-styled and JSON Schema-styled documentation endpoints, including runtime GET handlers and pretty-printed responses.
• Exposed new helpers in system and system/docs (mount_asyncapi, mount_json_schema, build_asyncapi_spec, build_json_schema_spec) and exported them via __all__.
• Extended TigrblApp and TigrblRouter with mount_asyncapi, mount_json_schema, asyncapi, and json_schema methods and wired default mounting when mount_system is enabled.
• Updated OpenRPC docs builder to ignore ops and paths related to the new async/json-schema docs so they are not listed as RPC methods.
• Added unit tests asserting the presence, content and pretty-printing of the new endpoints and builder helpers.

Testing

• Ran unit tests with pytest covering tests/unit/test_jsonrpc_openrpc.py and tests/unit/test_system_docs_builders.py which verify endpoint availability, methods, payload contents, and builder outputs; these tests passed locally.

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Codex Task