fix(burn-in): migrate Start-BurnInTest wrappers to Linux host paths

Replace Windows-hardcoded paths with Linux equivalents:
- RepoUrl → local Gitea instance (10.10.20.11:3100/Simone/burnin-dummy)
- TemplatePath/CloneBaseDir/ArtifactBaseDir/VmrunPath → /var/lib/ci/…
- `$scriptDir\Test-CapacityBurnIn.ps1` → Join-Path $PSScriptRoot (cross-platform)
- Remove `Split-Path -Parent $MyInvocation.MyCommand.Path` (redundant)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

scripts/Start-BurnInTest-Linux.ps1

@@ -51,18 +51,16 @@ param(
 Set-StrictMode -Version Latest
 $ErrorActionPreference = 'Stop'
 
-$scriptDir = Split-Path -Parent $MyInvocation.MyCommand.Path
-
 $burnInParams = @{
-    RepoUrl               = 'https://gitea.emulab.it/Simone/burnin-dummy.git'
+    RepoUrl               = 'http://10.10.20.11:3100/Simone/burnin-dummy.git'
     Branch                = 'main'
-    TemplatePath          = 'F:\CI\Templates\LinuxBuild2404\LinuxBuild2404.vmx'
+    TemplatePath          = '/var/lib/ci/templates/LinuxBuild2404/LinuxBuild2404.vmx'
     SnapshotName          = 'BaseClean-Linux'
-    CloneBaseDir          = 'F:\CI\BuildVMs'
-    ArtifactBaseDir       = 'F:\CI\Artifacts'
+    CloneBaseDir          = '/var/lib/ci/build-vms/'
+    ArtifactBaseDir       = '/var/lib/ci/artifacts/'
     GuestCredentialTarget = 'BuildVMGuest'
     GiteaCredentialTarget = 'GiteaPAT'
-    VmrunPath             = 'C:\Program Files (x86)\VMware\VMware Workstation\vmrun.exe'
+    VmrunPath             = '/usr/bin/vmrun'
     GuestOS               = 'Linux'
     BuildCommand          = $BuildCommand
     Parallelism           = $Parallelism
@@ -70,6 +68,6 @@ $burnInParams = @{
     RoundTimeoutMinutes   = $RoundTimeoutMinutes
 }
 
-& "$scriptDir\Test-CapacityBurnIn.ps1" @burnInParams
+& (Join-Path $PSScriptRoot 'Test-CapacityBurnIn.ps1') @burnInParams
 
 exit $LASTEXITCODE