Adds plugins/storage/migrate_test.go exercising migrateApp and MigrateLegacyMounts: single deploy phase, cross-phase grouping into one attachment, :ro and free-form volume options preserved on the attachment, idempotency on a second pass, the per-app flag-file fast path that skips already-migrated apps, and the name-collision refusal that aborts before draining. tests/unit/storage.bats gains an end-to-end case that stages a -v line via docker-options:add, runs storage:migrate, and asserts the synthesized colon form shows up in storage:list, the legacy-<hash> entry shows up in storage:list-entries, and the original -v line is gone from docker-options:report on both phases. To make that test (and operators with restored backups) practical, storage gains a storage:migrate <app>|--all subcommand backed by a new MigrateApp helper that skips the per-app flag file so a re-run actually re-scans.
storage:set is the in-place editor for an existing entry; size grows are passed through to a helm upgrade and Kubernetes-incompatible swaps (access-mode, storage-class) are rejected up front. storage:exec spawns a throwaway container that mounts the entry: docker run on docker-local entries, kubectl run with a Pod-spec override on k3s, falling back to bash then sh when no command is supplied. storage:wait blocks until a k3s entry's PVC reports Bound via the storage-status trigger, with a docker-local fast path that just checks the host directory. storage:report --global enumerates every registered entry and the apps that mount it, in text or JSON form.
Wires the new entry-management commands on top of the Entry type. storage:create accepts both docker-local entries (with idempotent host-directory creation) and k3s entries (which delegate PVC provisioning to a forthcoming scheduler-side storage-create trigger). storage:destroy refuses to remove an entry that any app still mounts. storage:ensure-directory now emits a deprecation warning. storage:mount and storage:unmount keep the existing colon-form behavior so this commit is non-breaking; the named-entry mount form follows in a later commit.
