According to the specification, `destructive_hint`, `idempotent_hint`, `open_world_hint`,
and `read_only_hint` of `ToolAnnotations` are optional with default values:
https://modelcontextprotocol.io/specification/2025-06-18/schema#toolannotations
This PR sets their default values in accordance with the specification.
Additionally, for readability, the hints have been reordered to follow the specification.