MCP tool implementations. Each submodule defines a single tool by
implementing SqliteServerTool and providing the associated input, output,
error, and value types.
Trait definitions for MCP server tools. The SqliteServerTool trait
provides a structured way to define tools with typed input, output, and
error types. Implementors declare their schema statically and provide a
synchronous handler; the trait takes care of generating the rmcp Tool
definition, JSON schemas, and the routing closure.