Changes
PR #1695 by ksylvan: Introduce One-Liner Curl Install for Completions
- Add one-liner curl install method for shell completions without requiring repository cloning
- Support downloading completions when files are missing locally with dry-run option for previewing changes
- Enable custom download source via environment variable and create temporary directory for downloaded completion files
- Add automatic cleanup of temporary files and validate downloaded files are non-empty and not HTML
- Improve error handling and standardize logging by routing informational messages to stderr to avoid stdout pollution