fix(preemptive-compaction): increase token threshold from 0.80 to 0.85

Raise the preemptive compaction trigger point from 80% to 85% to reduce false-positive compactions and allow longer session contexts before automatic compaction kicks in.

🤖 Generated with assistance of OhMyOpenCode

Author: code-yeongyu

src/hooks/preemptive-compaction/constants.ts

@@ -1,3 +1,3 @@
-export const DEFAULT_THRESHOLD = 0.80
+export const DEFAULT_THRESHOLD = 0.85
 export const MIN_TOKENS_FOR_COMPACTION = 50_000
 export const COMPACTION_COOLDOWN_MS = 60_000