P17-BIDIRECTIONAL-SAFETY: v2.0 Loss-Aware Transformation and Recovery Note

Documentation-only v2.0 methodological note in the existing P17-BIDIRECTIONAL-SAFETY version family. The newly original English PDF works through finite field-retention arithmetic, distinguishes a true inverse from checkpoint-assisted recovery, and specifies falsifiable rejection cases for lost critical fields and stale receipts. Three synthetic local P17 cases passed; this does not establish an observed reduction of harm, safe deployment, a successful restoration of a historical project, or independent reproduction. Only this explanatory PDF is uploaded; no earlier code, archive or third-party figure is included. Earlier version: https://doi.org/10.5281/zenodo.22179232 . CC BY 4.0 applies to this original PDF only and does not relicense earlier software or cited works. Computational and AI assistance is disclosed; Riccardo Giudici is responsible for the presentation as an independent systems orchestrator. No institutional endorsement is claimed.