fix(cli): support version flag

Summary

Adds standard --version / -V support to the published CLI binaries by wiring Commander to the package version.

Problem

The published mcp-handler@1.1.0 CLI already handles --help, but --version currently exits as an unknown option:

$ mcp-handler --version
error: unknown option '--version'

That makes it harder for users and setup scripts to verify which CLI version is installed.

Verification

• corepack pnpm build
• corepack pnpm test -> 30 tests passed
• node dist/cli/index.js --help -> exits 0 and shows -V, --version
• node dist/cli/index.js --version -> exits 0 and prints 1.1.0
• node dist/cli/index.js --definitely-not-a-real-flag -> exits 1 with Commander unknown-option error