Reproduce all 4 CCA-barrier claims: Thm4.2 non-composition (ratio 7.77), Thm4.3 eps'>=-ln(p), Thm5.5 Omega(2^ell) query complexity (slope 1.001)

Update logbook: Repro - Barriers to Counterfactual Credit Attribution

Expose claim-level theorem evidence and controls

Update logbook: Repro - Barriers to Counterfactual Credit Attribution

Update logbook: Repro - Barriers to Counterfactual Credit Attribution

Update logbook: Repro - Barriers to Counterfactual Credit Attribution