Correct the dependency classification of zod and @types/response-time

zod is imported for its runtime value export in src/mcpHandler.ts and
src/api.ts (z.object, z.string, and friends build the MCP tool schemas),
so it belongs in dependencies rather than devDependencies. Conversely
@types/response-time contributes nothing at runtime and belongs in
devDependencies alongside the project's other @types packages.

Nothing changes for the shipped plugin, since esbuild bundles from the
import graph rather than the manifest. This is about making package.json
an honest description of what the code actually needs, so that anyone
auditing the runtime surface reads the right list.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>