add observation reconciliation to extraction pipeline
instead of blindly appending new observations, each candidate is now
embedded and compared against existing observations in turbopuffer.
an LLM reconciler decides ADD/UPDATE/DELETE/NOOP per observation,
preventing duplicates and resolving contradictions at write time.
inspired by mem0's consolidation pattern.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>