Re-running `storage:mount <app> <entry> --container-dir <path>` against an existing `(entry, container_dir, process_type)` tuple now updates the attachment's mount-time fields in place instead of erroring with `already mounted`. Declarative tooling that wants to change `--volume-options`, `--volume-chown`, `--phase`, `--volume-subpath`, or `--volume-readonly` on an existing mount no longer has to unmount-then-remount, which briefly dropped the volume from `storage:report` and raced against any deploy that fired in the window. The legacy `host:container[:opts]` form keeps its strict `Mount path already exists.` failure.
Introduces the Entry and Attachment types that the storage plugin will use as the source of truth for named storage volumes, replacing the colon-delimited mount strings stored under docker-options. Entries persist as JSON under config/storage/entries and validate against scheduler-specific rules; attachments persist via the property list and capture how an app uses an entry. The legacy migration name synthesizer is also added so existing colon-form mounts can converge on a deterministic legacy- entry name. Existing storage commands are unchanged in this commit.
