feat(process): add Start-InfisicalProcess with event-based capture and friendly TimeSpan logging

- New cmdlet Start-InfisicalProcess: launches a child process with InfisicalSecret
  objects decrypted directly into ProcessStartInfo.Environment (optional -Prefix),
  additional -EnvironmentVariables, stdout/stderr capture, -AcceptableExitCodeList,
  -ParsingExpression regex parsing, -ExecutionTimeout / -ExecutionTimeoutInterval,
  -NoWait, -WindowStyle / -CreateNoWindow parameter sets, -Priority,
  -StandardInputObjectList, -SecureArgumentList, -LogOutput, -ContinueOnError, and
  ShouldProcess support. Secret plaintext is never written to user or machine scope.
- Stream capture uses event-based OutputDataReceived/ErrorDataReceived with
  BeginOutputReadLine/BeginErrorReadLine (no Task / ReadToEndAsync /
  GetAwaiter().GetResult()) to avoid PowerShell SynchronizationContext deadlocks.
- Restored the do { log; sleep } while (!HasExited) polling pattern using
  Thread.Sleep(pollInterval) so verbose "has been running for X" / "Checking again
  in Y" messages fire at the configured cadence even when no -ExecutionTimeout is
  supplied.
- TimeSpan values in verbose logs and on the result now use a friendly format
  ("7 seconds, and 364 milliseconds", "1 minute, and 30 seconds", "N/A" when zero)
  matching the legacy Start-ProcessWithOutput GetTimeSpanMessage scriptblock.
- Added DurationFriendly property to InfisicalProcessResult and a "The command
  execution took X" verbose line at completion.
- build.ps1 CmdletsToExport and Test-ModuleImports expected list contain 42 cmdlets.
- Added 9 xUnit tests covering FormatFriendly singular/plural, multi-unit joining,
  zero, sub-millisecond, and skip-zero-components behavior.

build.ps1

@@ -144,7 +144,8 @@ function Write-Manifest {
         'New-InfisicalScepDynamicChallenge',
         'Get-InfisicalScepMdmProfile',
         'Export-InfisicalScepMdmProfile',
-        'Write-InfisicalScepMdmProfileToWmi'
+        'Write-InfisicalScepMdmProfileToWmi',
+        'Start-InfisicalProcess'
     )
     AliasesToExport      = @()
     VariablesToExport    = @()
@@ -209,7 +210,7 @@ if (`$cmds.Count -eq 0) {
     throw "No cmdlets were exported by the PSInfisicalAPI module."
 }
 
-`$expectedCmds = @('Connect-Infisical','Disconnect-Infisical','Get-InfisicalSecret','New-InfisicalSecret','Update-InfisicalSecret','Remove-InfisicalSecret','Copy-InfisicalSecret','ConvertTo-InfisicalSecretDictionary','Export-InfisicalSecrets','Get-InfisicalProject','New-InfisicalProject','Update-InfisicalProject','Remove-InfisicalProject','Get-InfisicalEnvironment','New-InfisicalEnvironment','Update-InfisicalEnvironment','Remove-InfisicalEnvironment','Get-InfisicalFolder','New-InfisicalFolder','Update-InfisicalFolder','Remove-InfisicalFolder','Get-InfisicalTag','New-InfisicalTag','Update-InfisicalTag','Remove-InfisicalTag','Get-InfisicalCertificateAuthority','Get-InfisicalPkiSubscriber','Get-InfisicalCertificateProfile','Get-InfisicalCertificatePolicy','Get-InfisicalCertificate','Request-InfisicalCertificate','ConvertTo-InfisicalCertificate','Install-InfisicalCertificate','Uninstall-InfisicalCertificate','Export-InfisicalCertificate','Get-InfisicalCertificateApplication','Get-InfisicalCertificateApplicationEnrollment','New-InfisicalScepDynamicChallenge','Get-InfisicalScepMdmProfile','Export-InfisicalScepMdmProfile','Write-InfisicalScepMdmProfileToWmi')
+`$expectedCmds = @('Connect-Infisical','Disconnect-Infisical','Get-InfisicalSecret','New-InfisicalSecret','Update-InfisicalSecret','Remove-InfisicalSecret','Copy-InfisicalSecret','ConvertTo-InfisicalSecretDictionary','Export-InfisicalSecrets','Get-InfisicalProject','New-InfisicalProject','Update-InfisicalProject','Remove-InfisicalProject','Get-InfisicalEnvironment','New-InfisicalEnvironment','Update-InfisicalEnvironment','Remove-InfisicalEnvironment','Get-InfisicalFolder','New-InfisicalFolder','Update-InfisicalFolder','Remove-InfisicalFolder','Get-InfisicalTag','New-InfisicalTag','Update-InfisicalTag','Remove-InfisicalTag','Get-InfisicalCertificateAuthority','Get-InfisicalPkiSubscriber','Get-InfisicalCertificateProfile','Get-InfisicalCertificatePolicy','Get-InfisicalCertificate','Request-InfisicalCertificate','ConvertTo-InfisicalCertificate','Install-InfisicalCertificate','Uninstall-InfisicalCertificate','Export-InfisicalCertificate','Get-InfisicalCertificateApplication','Get-InfisicalCertificateApplicationEnrollment','New-InfisicalScepDynamicChallenge','Get-InfisicalScepMdmProfile','Export-InfisicalScepMdmProfile','Write-InfisicalScepMdmProfileToWmi','Start-InfisicalProcess')
 foreach (`$expected in `$expectedCmds) {
     if (-not (Get-Command -Name `$expected -Module PSInfisicalAPI -ErrorAction SilentlyContinue)) {
         throw "Cmdlet not found: `$expected"