Function source_outdated 

pub fn source_outdated(
    lock_entry: Option<&LockEntry>,
    source_checksum: &str,
    source_version: Option<&str>,
) -> bool

Returns true if an installed artifact is considered outdated relative to the source. Pure function — no I/O.

The three rules:

• No lock entry → outdated (artifact is untracked)
• source_checksum differs from lock’s source_checksum → outdated (content changed in source)
• Version newly present in source (source has a version, lock entry has none) → outdated