Add a test-only synth FrontendProvider that traverses compile() to
verified bytecode without PBS. Expose register/unregister on the static
registry and lock the obligation in specs 23 and 22.
Housekeep DSC-0063 with LSN-0065.
Move lifecycle assembly out of the PBS frontend into a common
AssembleLifecyclePipelineStage. PBS emits a typed IRLifecycleDeclaration;
the assembler owns wrappers, boot guard, and single project-init execution.
Housekeep DSC-0059 with LSN-0062, and include the DSC-0062 PVM/PBX
neutrality spec and lesson already present on this branch.
