pi-fold 4.2.7

pi-fold 4.2.7

Patch release.

• Forked sessions retain inherited folds, pending marks and dependent state, with child-owned checkpoints and historical parent measurement receipts. Thanks to @ShangHong-CAI for PR #9.
• Restore detects a provider receipt ahead of the ledger, retains existing folds and raw history, and rebuilds eligible folds on the next context pass. Missing ledger changes are reported rather than invented.
• Recovery and explicit /fold can size their fill when provider usage is unavailable. Ordinary automatic folding still requires a valid provider measurement; estimates never veto a request.
• Rollback notices describe the pending attempt. Failed recovery receipts accurately report transmission, and a failed retry queue is reported as not reissued.
• With auto-compaction off, the session tree stays intact and /fold supports explicit lossless salvage before retrying.

Validation: 81 runtime gates (9,767 assertions), lint, 118 experiment gates, on-disk SDK fork and reload, and offline SDK overflow recovery. The benchmark findings and all 102 carriage rows remain unchanged after genuine re-extraction.

The original long-session data-loss incident in #3 has not been reproduced end to end and remains open for investigation. This release fixes the demonstrated recovery and reporting gaps.