ship_cc.read lets cultcache-py refuse a zero-byte file (CultLib pins that); the test expects the refusal. New behavioural tests: ValidateJudgesProductsOnADraftAndInspectListsThem (through ShipAuthoringCommands.Run), AProductKeyAlreadyInTheCatalogExcludesThePackage, and price 1 in ASoldPackageHullNeedsAPrice. Tests only plus the add-on deletion; all commits build.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>