fix(windows): Invoke-Checked rejected the empty argument list every no-arg test uses (#512)

[localai-bot]

Closes #512.

windows-msvc-cpu failed on every PR with:

Cannot bind argument to parameter 'Arguments' because it is an empty array.

Invoke-Checked's $Arguments is [Parameter(Mandatory)] and six call sites pass @() — PowerShell treats an empty collection as "not supplied".

Fix

[AllowEmptyCollection()] alongside Mandatory, not a = @() default. The intent is that a caller must state its argument list, so omission should stay an error while an explicitly empty list is permitted. A fresh review proved both halves rather than accepting the argument: omission still raises missing mandatory parameters: Arguments, while the rejected = @() form silently accepts it.

Also adds Invoke-CheckedContractTests. The pre-existing contract suite passed green today — which proves it never exercised an empty-argument call, or it would have caught this. A 21-minute Windows build step was catching what a seconds-long local step should have. pwsh runs this path on Linux, so it does now.

Success criterion — narrow, and NOT "the job is green"

Closing #512 unmasked a hard crash. test_openai_api_server.exe dies with -1073740791 = 0xC0000409 (STATUS_STACK_BUFFER_OVERRUN) before doctest prints anything — zero Status: lines, zero assertions: lines, just the version banner. That binary had never once executed on Windows, so the crash was latent for as long as #512 was. Filed as #584.

What this PR claims, verified from completed jobs:

	windows-msvc-cpu
PR #578 (no fix)	contract step passes; build dies on empty array
PR #583	contract step passes; 0 occurrences of "empty array"; dies on #584's crash instead

So: the empty-array error is gone and the script now runs past all six sites on both real Windows runners. windows-msvc-cpu cannot go green until #584 lands, and windows-msvc-vulkan stays red on #514.

🤖 Generated with Claude Code

[localai-bot]

CI result — read from the completed job, not predicted

#512 is closed. Invoke-Checked now binds the empty argument list and
actually starts the process, which is exactly what #512 prevented.

windows-msvc-cpu on this PR:

Step	Result
Prove PowerShell, static CRT, and unsupported-tier contracts	success
Build and execute the native Windows CPU focused gate	failure — at a different, later point

The contract step passing on the real Windows runner is the direct proof: the
new Invoke-CheckedContractTests executes two empty-argument invocations, and
it is RED with the exact CI message without [AllowEmptyCollection()].

Baseline subtraction

	windows-msvc-cpu fails with
PR #578 (row/GATE-WINDOWS-POSIX-ENV), completed 17m02s	Cannot bind argument to parameter 'Arguments' because it is an empty array.
this PR	test_openai_api_server.exe exited with status -1073740791

The empty-array message is gone. The script ran past all six empty-argument
call sites and launched the executable.

windows-msvc-vulkan remains red on #514 as expected (#578 is still open); its
contract step also passed here.

What #512 was masking — filed as #584

Exception: D:\a\vllm.cpp\vllm.cpp\scripts\build-windows-release.ps1:31
  31 |          throw "$Program exited with status $exitCode"
     | ...\tests\Release\test_openai_api_server.exe exited with status
     | -1073740791

-1073740791 is 0xC0000409, STATUS_STACK_BUFFER_OVERRUN — a hard crash,
not an ordinary nonzero test exit. The process dies before doctest prints a
summary; the entire doctest output is the version banner and the --help hint,
with no Status: line and no assertions: line. Because
test_openai_api_server.exe had never once been executed on Windows, this
crash has been latent behind #512 for as long as #512 has existed.

That is a defect in the test binary, not in this PowerShell change — this PR
touches no src/, include/, or tests/ file — so it is filed separately as
#584 rather than fixed here, and windows-msvc-cpu cannot be fully green
until #584 lands.

This PR is still the correct and complete fix for #512: it converts a failure
that stopped the gate before it could test anything into a real test signal.