Introduce aegis_gitea_mcp.registry as the single name->handler source of
truth consumed by every transport adapter, moving TOOL_HANDLERS out of the
FastAPI server module. Add aegis_gitea_mcp.errors.ToolError so core handlers
no longer import fastapi.HTTPException; raw_tools now raises ToolError and the
HTTP adapter maps it back to HTTPException, preserving status codes and audit
behavior. Add a subprocess boundary test asserting the core imports without
pulling in fastapi/uvicorn/starlette.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
