fix(m3-conceptual-systems-reconcile): re-freeze decisive splits from harder calibrated pools, reconcile manifest counts, fix source refs, set systems in_band=true

- Regenerated conceptual-reframes-decisive.jsonl (224 items) and
  systems-product-strategy-pairwise-decisive.jsonl (117 items) by merging
  old candidate items with harder-calibrated pool items.
- Fixed non-existent source_file references (authored/harder-conceptual.jsonl
  and authored/harder-systems.jsonl) to point at real harder-pool JSONL files
  and the generator script.
- Replaced item_counts in both manifests with exact counts from JSONL
  (programmatically verified: every count matches).
- SYSTEMS: set in_band=true, dropped CEILING-NEEDS-HARDER-DATA exemption,
  recorded as valid powered candidate (aggregate baseline 0.574 in [0.40,0.70]
  per library/harness.md aggregate rule for binary families).
- CONCEPTUAL: retained honest CEILING-NEEDS-HARDER-DATA note (~92% aggregate,
  ~8pp headroom), reconciled counts.
- Both decisive splits verified: >=1 target + >=1 distractor + 0 ambiguous
  + 0 calibration-only. Manifest counts exactly equal JSONL contents.