ForgeFlow 0.10.8

Self-contained checksum verification

Binary and source update helpers no longer depend on the optional PowerShell Get-FileHash cmdlet.
Both helpers calculate checksums directly with the built-in .NET SHA-256 implementation.
A real Windows regression test clears PSModulePath and verifies the downloaded binary successfully in that minimal environment.
The helper still validates the exact published checksum before waiting for ForgeFlow to exit or changing installed files.
This release retains the reliable non-detached launcher and server-to-repository recognition improvements from 0.10.6 and 0.10.7.