Adding JSON Schema validation of API requests

[jmvrbanac]

Currently, no validation occurs for the JSON in API requests.

[m13v]

definitely worth adding, unvalidated API requests are a security risk and make debugging way harder since bad data can cause cryptic errors deep in the stack. for the implementation, validate at the handler level before any business logic runs. we use JSON schema for our tool definitions in the MCP protocol and validating the parameters before execution catches a lot of issues early. one tip: generate your schemas from your data types rather than writing them by hand, it's less error-prone and stays in sync with your code automatically.

[m13v]

our MCP server that uses JSON schema for tool parameter validation: https://github.com/mediar-ai/terminator/blob/main/crates/terminator-mcp-agent/src/server.rs - validates inputs against the schema before dispatching to tool handlers