Memory correctness cleanups (contradiction fallback, note merge, batch dedup)

[prakashUXtech]

Three related correctness gaps in the memory pipeline (2026-07-03 dev audit, commit 2ad0eb9):

• Raw-text contradiction fallback sets superseded_by = "raw-text-contradiction" (a sentinel string in an id field) and suppresses the old fact with no replacement stored, so the soul loses the knowledge entirely. manager.py:1156-1166; semantic recall filters it out at semantic.py:99.
• note()'s documented contradiction detection is a no-op (_ = detect_contradictions at soul.py:1513), and its MERGE branch sets the old entry's superseded_by without the new entry's supersedes back-edge or a supersede-audit record, so note-driven merges are invisible to provenance (soul.py:1587-1612, :2263).
• observe() snapshots existing facts once before iterating a batch, so two near-identical facts extracted from the same interaction are never compared and both persist (manager.py:1049). The dream sweeper only catches overlap >= 0.85, so 0.6-band pairs survive.

Impact: degraded recall, lost facts, unreconstructable provenance, and duplicate accumulation in the capped semantic store.

[github-actions]

This issue has been automatically marked as stale because it has not had activity in the last 30 days. It will be closed in 14 days if no further activity occurs. If this is still relevant, please comment or update.

[github-actions]

Closing due to inactivity. Feel free to reopen if still relevant.

[prakashUXtech]

Reopening — this was auto-closed by the stale bot on 2026-08-17, not because it was fixed. The work is still in active review in #302. Adding pinned so the bot leaves it alone until the fix actually merges.