* docs: update CLAUDE.md and user docs for error handling and podcast retry
Add missing documentation for features introduced in v1.7.2 (#590) and
v1.7.3 (#595): error classification system, global exception handlers,
ConfigurationError, podcast failure recovery, and retry endpoint.
* chore: update uv.lock
- Replace old docs structure with new comprehensive documentation
- Organize into 8 major sections (0-START-HERE through 7-DEVELOPMENT)
- Convert CONFIGURATION.md, CONTRIBUTING.md, MAINTAINER_GUIDE.md to redirects
- Remove outdated MIGRATION.md and DESIGN_PRINCIPLES.md
- Fix all internal documentation links and cross-references
- Add progressive disclosure paths for different user types
- Include 44 focused guides covering all features
- Update README.md to remove v1.0 breaking changes notice
