Module error 

Crate-wide error type for the PkgMgr subsystem.

PkgError is the single error type for all PkgMgr operations (manifest parsing, lockfile I/O, git fetch, CLI). It is distinct from the existing crate::ResolveError, which covers runtime resolve() failures. Additional variants are added by subsequent subtasks.

Enums

PkgError

Crate-wide error for PkgMgr operations.