cloneSettings() copies 85+ fields including 6 nested usage Maps and the
bandwidth schedule array. With ~700ms emit interval most snapshot ticks
clone identical settings. Add a time-based cache (400ms TTL) so most
snapshots reuse the previous clone.
Settings are mutated in-place by hot paths (provider usage tracking, debrid
key counters), so a reference check wouldn't catch changes — but the 400ms
TTL window is short enough that user-visible setting changes still appear
within one render cycle. replaceSettings() explicitly invalidates the
cache for immediate visibility on user setting changes.
The 4 architecturally-invasive items I considered for this round —
recordSpeed batching (already 120ms-bucketed, false alarm), full IPC state
diffing (392 mutation sites, too risky), list virtualization (variable
package heights make it complex), and per-channel settings/stats split
(invasive type changes) — are deferred. This caching change captures most
of the practical settings-clone savings without the architectural risk.
All 140 download-manager tests green.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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