feat(skills): wire dedup_threshold config into trace_extractor

[bug-ops]

Description

trace_extractor.rs:76 hardcodes dedup_threshold = 0.90 instead of reading from SkillsConfig.dedup_threshold which already exists.

Expected Behavior

TraceExtractor reads dedup_threshold from SkillsConfig so operators can tune the dedup zone without recompiling.

Actual Behavior

dedup_threshold is hardcoded to 0.90.

Found in

Code review of #4447 / PR feat/issue-4447/autoskill-a1-a2.