Three duplicate ErrorSeverity enums (data/error.rs, data/validation.rs,
database/error.rs) with variants Low/Medium/High/Critical now use the
canonical definition in common::error::ErrorSeverity.
Extended common's ErrorSeverity with Low, Medium, High variants (alongside
existing Debug, Info, Warn, Error, Critical) and added PartialOrd/Ord derives
so both severity models coexist in a single type.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Move 17 library crates into crates/, CLI binary into bin/fxt,
consolidate 10 test crates into testing/, split config crate
from deployment config files.
Root directory reduced from 38+ to ~17 directories.
All Cargo.toml paths and build.rs proto refs updated.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
