fix: catch tool registration errors

[cdcabrera]

What is it?

• fix: catch tool registration errors
  • docs, add terms, definitions for JSON, Zod, raw Zod
  • index, annotate JSON inputSchema, tools-as-plugins
  • server.schemas, normalizeInputSchema, add setting, allow returning undefined
  • server.tools, makeProxyCreators, use defensive normalizeInputSchema
  • server, try-catch tool registration, skip tools without zod schemas

Notes

• build(deps): bump @modelcontextprotocol/sdk from 1.27.1 to 1.28.0 #154 released a potential breaking change as "fix." patch potential fail point
• this work can go in before or after since it's applying logic
• pf mcp already attempts to convert the json schema to a zod schema (zod released a feature to do this type of conversion) for "tools as plugins". we do not perform this zod conversion for internal tools, it is expected you use a zod/raw zod (zod-like) object.
  • this is a fallback for one-off scenarios where a non-zod schema manages to get through to registration
  • we now log and skip the tool registration
  • we wrap the registration in a try/catch for a smoother consumer experience
• mcp sdk 1.28.0 still seems to allow a "zod-like" input schema, this may become stricter in the future and would require us to potentially tighten checks more
• work includes a minor refactor and expanded unit testing of the schema normalization logic to support both strict Zod internal tools and flexible JSON-based external plugins.

Updates issue/story

ongoing

caused by #154