Description

The current README is a one-liner. Users need installation instructions, usage examples, and common recipes so they can adopt the tool quickly.

Acceptance Criteria

• Installation section: download binary, or brew install (if published), or build from source
• Basic usage: echo 'name,age\nAlice,30' | sql-pipe 'SELECT * FROM t'
• At least 5 real-world usage examples (filter, aggregate, join with multiple tables if supported, etc.)
• Documents the input format requirements (CSV with header row, table name t)
• Documents exit codes and error messages
• Badges: build status, latest release, license

Notes

• Keep examples copy-pasteable and self-contained
• Mention --help flag (to be added via separate issue if not yet present)