- Floor the effective max_concurrent at 1 on the read path (quota.resolve)
and in the claim SQL (GREATEST(..., 1)). admin_set_quota already floors on
write and the sysconfig default's min is 1, but a stray stored 0 (direct DB
edit) would diverge the two "at limit" checks — the SQL claim-window
exclusion can't see a user "capped" with zero running jobs, while
at_concurrency_limit can — reopening the starvation the fairness fix closes.
Keeping the effective limit >= 1 makes the two checks provably agree.
- shared_with_me now orders by (created_at DESC, id DESC) to match
list_downloads, so the newly-added 500 cap has a stable boundary among
same-timestamp shares instead of a non-deterministic one.
- 0062 upgrade loop: rename the unused loop var "table" to "_table"
(matching the underscore-marked "_col").
Test: a stored max_concurrent=0 flooder no longer wedges the claim loop.
peter