Remove createCursorRole, createHermesRole, createLlmRole, createReActRole
from public API — all superseded by createRole(adapter, prompt, schema, extract).
Source files retained as internal implementation.
Also remove unused type exports: CliPromptFn, CursorRole*, HermesRole*,
LlmPromptFn, LlmRole*, ReActRole*, ReActTool. Keep LlmMessage and
MetaExtractConfig (used internally).
Refs #277