fix(setup): preserve registration identity and recovery ownership
Keep layered environment choices, current byte-exact recovery snapshots, and package-manager failure details. Report pinned package drift without claiming runner resolution. Retain failed Linux installer cleanup for host-owned retry while preserving the install outcome.
Reviewed fixes include #2632, #2769, #2783, #2959, #2979, #2983, #2995, #3009, and #2559.
Validation: 98 focused setup/registration tests passed; 45 Linux installer tests passed. Real Linux package installation remains unverified.