Return protocol errors for invalid tool arguments

[FU-max-boop]

Summary

• let SDK-generated tool input validation errors propagate as JSON-RPC InvalidParams errors
• keep tool handler exceptions and output validation failures as tool-level { isError: true } results
• update Zod/Standard Schema integration coverage and add a changeset

Validation

• npx -y pnpm@10.26.1 --filter @modelcontextprotocol/test-integration test -- test/server/mcp.test.ts test/standardSchema.test.ts
• npx -y pnpm@10.26.1 --filter @modelcontextprotocol/server test
• npx -y pnpm@10.26.1 --filter @modelcontextprotocol/server typecheck
• npx -y pnpm@10.26.1 --filter @modelcontextprotocol/test-integration lint
• npx -y pnpm@10.26.1 --filter @modelcontextprotocol/server lint
• npx -y pnpm@10.26.1 --filter @modelcontextprotocol/server build
• npx -y pnpm@10.26.1 run sync:snippets --check

Fixes #2162

[changeset-bot]

🦋 Changeset detected

Latest commit: 1a902a5

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@modelcontextprotocol/server	Patch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[pkg-pr-new]

Open in StackBlitz

@modelcontextprotocol/client

npm i https://pkg.pr.new/modelcontextprotocol/typescript-sdk/@modelcontextprotocol/client@2172

@modelcontextprotocol/codemod

npm i https://pkg.pr.new/modelcontextprotocol/typescript-sdk/@modelcontextprotocol/codemod@2172

@modelcontextprotocol/server

npm i https://pkg.pr.new/modelcontextprotocol/typescript-sdk/@modelcontextprotocol/server@2172

@modelcontextprotocol/express

npm i https://pkg.pr.new/modelcontextprotocol/typescript-sdk/@modelcontextprotocol/express@2172

@modelcontextprotocol/fastify

npm i https://pkg.pr.new/modelcontextprotocol/typescript-sdk/@modelcontextprotocol/fastify@2172

@modelcontextprotocol/hono

npm i https://pkg.pr.new/modelcontextprotocol/typescript-sdk/@modelcontextprotocol/hono@2172

@modelcontextprotocol/node

npm i https://pkg.pr.new/modelcontextprotocol/typescript-sdk/@modelcontextprotocol/node@2172

commit: 1a902a5

[FU-max-boop]

Closing this as a duplicate of my earlier PR #2169, which already addresses #2162. I carried the useful changeset from this branch into #2169 so review can stay concentrated there. Sorry for the noise.