Release v0.5.1

[Polarnova]

Summary

• publish CryptBoolean v0.5.1 with the reviewed Chapter 6 source-recovery additions
• formalize Hadamard/difference-set and Cayley-graph results, Maiorana--McFarland balance and bent subspaces, further decompositions, classes D₀/D/C, secondary specializations, and the exact PSap count
• reuse and promote shared FABL/Chapter 2/Chapter 4/Chapter 6 combinators instead of duplicating proofs
• synchronize the Chapter 6 inventory, dependency/fidelity audits, Blueprint associations, manifest expectations, README, and package version
• retain the remaining cited or underspecified source-recovery families visibly in the inventory

Validation

• nine affected production modules built successfully
• six affected Chapter 6 Blueprint modules built successfully
• forbidden-token audit passed
• statement-style audit passed: 222 statements, 219 formalized, 3 open
• Chapter 6 inventory self-check passed: 70 formalized statements, 441 declarations, 189 dependency edges, 18 source-recovery records
• staged diff integrity check passed

The complete root library, axiom audit, Blueprint, manifest, and publication build remain delegated to GitHub Actions as required by the repository contract.