FR-PLAT-AND-4's Rust half, and FR-PLAT-AND-3's resumability with it. The
queue's claim_next, complete, fail and recover_orphaned had no callers
outside their own tests, so the jobs table accumulated rows nothing ever
ran.
It also fixes a claim that was not safe across two connections: the
deferred transaction took a read lock for the SELECT and only tried to
upgrade at the UPDATE, so in WAL the second worker got
SQLITE_BUSY_SNAPSHOT, which a busy handler cannot retry away. It never
double-claimed, but the loser errored. Now one UPDATE ... RETURNING.
No handler is wired, deliberately. The only enqueue site reachable in
the shipping app produces remote thumbnail jobs already served by the
async grid worker, and inventing a second network path blind is not
worth a requirement reading as covered on the strength of plumbing.
Verified: clippy -D warnings clean, 376 dr-catalog and 548 dr-ui tests,
18 runner tests including four-thread contention and crash recovery.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
# Conflicts:
# docs/traceability.md
# ui/dr-ui/src/library.rs
# ui/dr-ui/src/settings_ui.rs
dtourolle
da3b1487f9