Manuscript-level source-reading evidence

Ledger v18: 51 selected-section manuscript records and 147 source hashes among 719 manuscripts. The other 668 await earlier-reading imports or individual review. All 372 family assessments remain separate first-pass coverage. Neither count accepts proofs.

Family 235 adds four manuscript records for limiting random-SAT thresholds, two variance results and threshold computability. Four PDF first pages were visually inspected. Exact extents, formal boundaries and finite benchmark evidence. Source algorithms, full proofs and kernels were not executed; earlier evidence remains preserved.