Upgrade And Rollback Simulation Receipts

The receipt schema is:

schemas/upgrade-rollback-receipt.schema.json

The first concrete Redis receipts are:

recipes/bitnami/redis/25.5.3/operations/default-to-reuse-existing-secret/upgrade-simulation-receipt.yaml
recipes/bitnami/redis/25.5.3/operations/reuse-existing-secret-to-default/rollback-simulation-receipt.yaml

These receipts model the first Redis day-2 transition:

default rendered Secret
-> reuse existing target Secret
-> rollback to the default generated fact

Each receipt records:

before and after variant revision
before and after rendered object digest
diff digest
preserved changes
dropped changes
required operator decisions
hook, CRD, PVC, and generated-fact risks
conflicts
result

The next expansion is true old-chart-version simulation, but the receipt shape and verifier contract are now concrete.