Function validate_speculative 

pub fn validate_speculative(
    source: &str,
    inputs: &InputMap,
    lock: Option<&FlakeLock>,
) -> ValidationResult

Like validate_full but skips the lock-drift lints (lint_follows_stale and lint_follows_stale_lock) that compare declared edges in flake.nix against flake.lock.

For speculative validation during a multi-step apply. The lockfile cannot reflect mid-batch text edits, so a freshly-added follows always looks stale relative to the on-disk lock. Running lock-drift lints there would flag every in-progress edit as drift.