handleBatchDone's terminal-job auto-cap (introduced in 3.3.0) lived
inline as a manual two-pass loop over queueJobs. Pull the algorithm
into lib/queue-prune.js as pure pruneOldestTerminalJobs(jobs, limit)
that returns { kept, dropped } so the caller can clean up its index/
selection in one go. Same single implementation backs runtime and
tests via dual-environment loader (CommonJS module.exports for Node
tests, window.QueuePrune global for the renderer via index.html
script tag).
Coverage:
- Empty / null / non-array input → no-op
- All-non-terminal → no-op (regardless of limit)
- Terminal count ≤ limit → no-op
- Terminal count > limit → drops oldest by insertion order
- Mixed queue: non-terminals always kept, only terminals dropped
- limit=0 → drops every terminal
- Negative / NaN / Infinity limits → safe no-op
- Malformed entries (null, missing status) handled without throwing
- Large-queue stress (5000 done jobs) keeps newest 500
- TERMINAL_STATUSES set covers exactly done/skipped/error/aborted
Renderer uses window.QueuePrune?. so a failed script load just
disables the prune rather than crashing every batch-done. 107/107
tests green.
