Description

Two critical helper classes are entirely static with no interfaces:

ProcessHelper (src/Servy.Core/Helpers/ProcessHelper.cs)

• GetCpuUsage(int pid), GetRamUsage(int pid), ResolvePath(), ValidatePath(), FormatCpuUsage(), FormatRamUsage()
• Called from MainViewModel.RefreshServiceInternal (lines 900–901) and PerformanceViewModel.OnTickAsync (lines 310–313)
• Tests must deal with real Process.GetProcessById calls

ProcessKiller (src/Servy.Core/Helpers/ProcessKiller.cs)

• KillProcessesUsingFile(), KillProcessTreeAndParents()
• Called from MainWindow cleanup and ResourceHelper
• Tests cannot verify process-killing behavior

Impact

Any test of refresh, performance, or cleanup logic requires real process handles. Cannot verify behavior with specific PIDs, failure scenarios, or access-denied conditions.

Suggested fix

Wrap behind interfaces (IProcessHelper, IProcessKiller) and inject. The existing code uses instance-based DI for most other services — these two are the main holdouts.