feat(reflection): split inherit/derive memories and weight derive focus

[furedericca-lab]

Summary

• split reflection persistence into separate Inherit and Derive entries while keeping category=reflection
• add logistic weighting for Derive injection instead of relying on only the latest reflection row
• keep legacy combined reflection rows readable/injectable without a required migration
• extract part of the reflection metadata/slice/store logic out of index.ts

Why

• stable carry-over rules and short-lived next-run deltas should not live in the same reflection memory shape
• the previous derive path was too dependent on the latest reflection row
• reflection injection needs a decay-aware way to surface recent execution deltas without changing global retriever scoring
• the reflection path in index.ts had grown enough to justify a focused structural cleanup

Changes

• store split reflection rows with metadata.reflectionKind = "inherit" | "derive"
• display new rows as reflection:Inherit and reflection:Derive
• preserve a legacy-safe read/display path for old combined reflection rows
• apply logistic derive weighting during reflection loading/injection only
• use defaults:
  • midpointDays = 3
  • k = 1.2
  • fallback derive base weight = 0.35
• keep <inherited-rules> sourced from inherit memories only
• keep <derived-focus> sourced from derive memories only
• add focused tests for split persistence, legacy compatibility, subtype display tags, and derive weighting

Verification

• npm test

Risks / Compatibility

• compatibility is preserved by keeping category=reflection and continuing to read legacy combined reflection metadata
• derive injection behavior now aggregates multiple recent derive rows with decay instead of only using the latest row
• no global retriever scoring behavior was changed