[EHotwagner]

Exercises interrupted current supplier /4 source commits through the existing writer, lock, CAS and readback path. A finite controlled-test factory selects one fixed failure point: before writing, before file flush, before replacement, after replacement before fresh readback, or before cold reopen. Both ordinary constructors select no cut; no arbitrary fault callback or alternate journal is introduced.

The genuine signed zero and selected journeys exercise all five cuts through six transitions per branch: 60 cases. Each failed Stage returns commit uncertainty and retains the exact prior or proposed record, including original identity and full custody. A later explicit fresh read with current cryptographic revalidation may authenticate replaced source bytes while durability remains Unknown. Each cut asserts ACK/host reservation refusal and zero runner run, cleanup and recovery calls.

Independent source, evidence and final composition reviews accepted. A bounded SDK 10.0.400 job on exact functional source b1304e7 passed locked restore, strict Release build and the maintained integration Fact, retaining the two earlier build failures separately. Final head ffa80b4 passed Bootstrap qualification: zero build warnings/errors and all focused results passed (46 allocation, 80 executor, 55 inert, 29 transport, 47 process and 714 architecture), including the expanded signed/store Fact. The maintained dependency policy and exact 29-project NuGet.org transitive vulnerability audit passed with no listed vulnerabilities. Full coherent validation passed. Merge readback must still bind the protected tree to this tested head.

The owning contract and immutable Atlas history capture the source/durability boundary. These controls target current /4 source records. Production enrollment, native/provider effects, physical durability and ACK authority remain outside this source result.