with_writer/with_reader/blocking_read release their slot/pool
connection only on the normal return — a panic inside the closure
wedged the single writer slot forever (Writer::acquire waits on a
condvar) and permanently shrank the reader pool (outstanding never
decremented on abandonment). The seams now ride RAII drop-guards
(ConnLease's idiom): the normal arm defuses and releases unchanged;
the unwind arm drops the unknown-state connection and takes the
established abandonment dispositions — Writer::replenish() (the tick's
poisoned arm as a substrate method, the writer now holding its path)
and Readers::abandon() (outstanding decrement + pool-locked notify).
Three panic-injection tests pin the properties; no reachable panic
path exists in production — this is the defense-in-depth armor the
review scoped. Task: sqlite-fix-seam-panic-safety.
glm-5.3-flash