Handle metadata flags before server startup

[wowsofine]

Summary

• handle --help, -h, --version, and -v before starting the stdio MCP server
• keep the existing no-arg stdio startup path unchanged
• add regression coverage for CLI metadata flags

Why

The published mcp-server-alchemy bin currently treats metadata flags as normal server startup, so --version and --help print the stdio startup message instead of returning CLI metadata.

Validation

• pnpm exec tsx --test tests/cli-metadata.test.ts
• pnpm build
• pnpm test
• pnpm lint
• pnpm exec eslint index.ts tests/cli-metadata.test.ts
• pnpm pack --pack-destination /tmp/automoney-alchemy-pack
• npm exec --yes --package=/tmp/automoney-alchemy-pack/alchemy-mcp-server-0.3.0.tgz -- mcp-server-alchemy --version
• npm exec --yes --package=/tmp/automoney-alchemy-pack/alchemy-mcp-server-0.3.0.tgz -- mcp-server-alchemy --help
• no-arg tarball smoke still starts the stdio path