Add support for -file-format flag to llgo build command allowing users to specify output format independently of target configuration.
Changes:
- Add -file-format flag supporting bin, hex, elf, uf2, zip formats
- Implement two-stage conversion: firmware format → file format
- Add ConvertOutput function with hex format conversion support
- Update build logic to handle different modes (build vs run/install)
- Add verbose logging for conversion operations
For build command: only convert firmware when -file-format is specified
For run/install commands: always convert firmware when target requires it
🤖 Generated with [Claude Code](https://claude.ai/code)
Co-Authored-By: Claude <noreply@anthropic.com>
