Coordinate foreground search and background inference CPU budgets

AGENTS.md

@@ -46,6 +46,11 @@ readiness without completed release gates and recorded evidence.
   graphs before SQL activation; retain the query model/LRU across publication
   instead of repeating warmup under the foreground mutex. Measure startup,
   actual first input, and warm p95 separately.
+- Desktop CPU threads are a shared inference budget (settings version two),
+  default two and hardware-clamped. Keep foreground priority and one background
+  thread; yield between document encodes. Trace admission separately from native
+  inference. This does not bound decoder, extraction or ANN CPU work. Do not
+  claim preemption of an already executing media encode on a one-thread budget.
 - UI should belong to each OS: native typography/chrome/dialogs, themes,
   keyboard access, reduced motion and high contrast. Brief transitions must not
   delay requests. Preserve selection/focus as progressive results arrive.