Requires sandbox_case ~> 0.4.0-rc (FunWithFlags isolated via a persistence
adapter, not bytecode patching); fixes a FunWithFlags isolation leak by
requiring the FWF read-cache be disabled in test; adds coverage for
self-scheduled post-mount LiveView patch chains.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>