Re-mounting the calendar no longer records a duration sample or
announces the previous result, explanation or rejected explanation.
Starting a calculation during a cancellation announces loading and
keeps focus where it is. Only rejected explanation deliveries are
announced, as before. Replacement tests now replace a real plan.
Refs #275, #274
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
PlanningCalculationService now builds the submitted request, owns the
pending and accepted calculation state, and delivers explanations for
the accepted calculation only. The duration estimator reads the same
request. The calendar and leave-balance summary consume the accepted
outcome instead of coordinating writable state on the input service.
Refs #275
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>