Phase 5: Replace all Box<dyn Error> return types with anyhow::Result<T>
throughout the codebase. Replace string-based Err("msg".into()) and
format!().into() patterns with bail!() and anyhow!() macros. Fix
dirs::home_dir().unwrap() in settings.rs to use a fallback path instead
of panicking when HOME is unset. Remove stray use std::error::Error
imports no longer needed.
Phase 6: Add From<&User> for CacheUser in models/user.rs and
From<&Laboratory>/From<&Laboratories> for CacheLaboratory/CacheLabsWrapper
in models/laboratory.rs. Simplify commands/login.rs to use .into()
conversions, removing the redundant to_cache_user() and to_cache_labs()
helper functions.
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
