feat(storage): enforce CKB deletion, retention, backup, and restore safety

[akoita]

Parent program: #78

Outcome

Apply one explicit lifecycle policy across managed CKB sources, normalized facts, indexes, run references, backups, and retained exports.

Scope

• Coordinate writers through locks or leases before repair, cleanup, deletion, export, or restore.
• Use prospective journal evidence to distinguish owned managed entries from unknown data.
• Reconcile interrupted managed writes and repair missing or corrupt owned data where proof is sufficient.
• Define retention and deletion behavior for raw sources, normalized records, lexical indexes, future vector indexes, run references, backups, and approved exports.
• Preserve unknown or legacy unjournaled entries unless the user makes a separately justified decision.
• Validate portable backup, export, restore, and migration behavior.

Acceptance criteria

• Confirmed CKB deletion removes owned managed data and indexes according to policy without deleting unknown entries.
• Interrupted operations recover deterministically under writer coordination.
• Backup and restore preserve logical CKB identity, provenance, and source versions without treating origin bindings as portable continuity.
• Retained immutable audit or export records are explicit.
• Failure-injection and migration tests pass.
• pnpm validate passes.

Parent program

• feat(knowledge): manage reusable candidate knowledge bases and source lifecycle #78

Dependency

• feat(knowledge): bind applications to explicit CKB and source-version snapshots #111