Fixes#4381. Follow-up to the Linux lifecycle audit in #4227.
Keep managed source hashing on bounded reads through its existing FileHandle owner. Preserve exact opaque cancellation reasons before filesystem or cleanup interpretation, retain genuine failed closes, block unsafe admission, and recover the same provider after verified cleanup.
Validated with 484 related tests, source/docs checks, seven real Linux provider cancellation/recovery scenarios using an unchanged official Microsoft .NET assembly, and paired actual CLI/stdio MCP Evidence workflows. Normal completed-task timing, CPU, memory and token proxies remained comparable.
Adopts xu91102/rea commit ebeec580c839f2f72144282a44f4e11ea5759843 with independent Linux verification and cancellation-reason hardening.
Co-authored-by: hhang <169027046+xu91102@users.noreply.github.com>
