Function evaluate_plan 

pub fn evaluate_plan<F: Filterable + ?Sized>(
    rules: &[FilterRule],
    msg: &F,
    ctx: &EvalContext<'_>,
    regex_cache: &RegexCache,
) -> EvalOutcome

Evaluate rules against a message and resolve them into execution-ready outcomes.

Like collect_matches this is first-match-wins, but the returned plan additionally resolves the actions that need runtime context:

• vacation: the reply-to sender is taken from envelope data (falling back to the header From address); the subject defaults to Re: <original subject>; a reply already sent (per EvalContext::seen_before) suppresses the outcome, and an unroutable reply emits EvalWarning::VacationNoSender.
• notify: unrecognized method schemes emit EvalWarning::UnknownNotifyMethod.

Pure and synchronous: no I/O, never panics.