V209: a storage profile's copies are counted per kind of bucket, local and cloud.

A profile used to say "N copies of each file" and let placement pick any N buckets. It now says how many copies go to local buckets and how many to cloud buckets, so a profile can keep two copies on the server's own disks and one in the cloud, which survives the server:

• copies_local (0..5) — copies on local buckets;
• copies_cloud (0..5) — copies on cloud buckets (S3, B2, R2, Tigris).

copies_originals stays and is now the total: the CHECK below keeps it equal to copies_local + copies_cloud, so everything that reads the old column (min_copies_on_write is bounded by it, an older core on the same database) still sees how many copies a file has. copies_variants is not used any more; the application keeps it equal to the total.

Backfill

Existing profiles are split the way their buckets are, local first: the cloud share is as many of the profile's copies as the local buckets cannot take, up to the cloud buckets it has (active, enabled); the rest is local. A profile with no bucket yet keeps all its copies local. The total never changes, and revision is not touched, so no file is placed again by this migration.

The backfill runs only when the columns are added, so a re-run never overwrites a split an admin chose.

Locks

ALTER TABLE on the (tiny) profiles table, one UPDATE of its rows.