bump-core-req

Updates the minimum core version requirement for a fleet plugin in all three canonical places: required_core_version and requires["claude-code-hermit"] in hermit-meta.json, and the dependencies entry in plugin.json. Use this skill whenever the user says "bump core requirement", "raise required_core_version", "make <fleet> require core X.Y.Z", "update min core for <fleet> plugin", or finishes shipping a core feature that fleet plugins need to declare they depend on. Also trigger when the user says "align fleet deps" or asks which version the fleet plugins are pinned to and wants to update them.