refactor: migrate to the v2 MCP SDK packages

Replaces @modelcontextprotocol/sdk ^1.30.0 with @modelcontextprotocol/server
^2.0.0, and @modelcontextprotocol/client ^2.0.0 in devDependencies for the
test harness. Applied with @modelcontextprotocol/codemod v1-to-v2, which
rewrote the import paths and wrapped every inputSchema raw shape in
z.object() — raw shapes are deprecated in v2.

Tool names, titles, annotations and argument descriptions are unchanged.