[WSLC] Add E2E version command test and strengthen unit test

- Add WSLCE2E_VersionCommand E2E test in WSLCE2EGlobalTests verifying
  stdout, empty stderr, and exit code for 'wslc version'
- Add assertion to VersionCommand_HasNoArguments unit test to verify
  only the auto-added --help argument is present

Authored-By: Pooja Trivedi <trivedipooja@microsoft.com>
Co-Authored-By: Claude Sonnet 4.6

Author: Pooja Trivedi

test/windows/wslc/WSLCCLICommandUnitTests.cpp

@@ -116,6 +116,8 @@ class WSLCCLICommandUnitTests
     {
         auto cmd = VersionCommand(L"wslc");
         VERIFY_ARE_EQUAL(0u, cmd.GetArguments().size());
+        // Test out that auto added help command is the only one
+        VERIFY_ARE_EQUAL(1u, cmd.GetAllArguments().size());
     }
 
     // Test: Verify RootCommand contains VersionCommand as a subcommand

test/windows/wslc/e2e/WSLCE2EGlobalTests.cpp

@@ -44,6 +44,12 @@ class WSLCE2EGlobalTests
         RunWslcAndVerify(L"INVALID_CMD", {.Stdout = GetHelpMessage(), .Stderr = L"Unrecognized command: 'INVALID_CMD'\r\n", .ExitCode = 1});
     }
 
+    TEST_METHOD(WSLCE2E_VersionCommand)
+    {
+        WSL2_TEST_ONLY();
+        RunWslcAndVerify(L"version", {.Stdout = GetVersionMessage(), .Stderr = L"", .ExitCode = 0});
+    }
+
 private:
     std::wstring GetHelpMessage() const
     {
@@ -56,6 +62,11 @@ class WSLCE2EGlobalTests
         return output.str();
     }
 
+    std::wstring GetVersionMessage() const
+    {
+        return std::format(L"wslc v{}\r\n", WSL_PACKAGE_VERSION);
+    }
+
     std::wstring GetDescription() const
     {
         return L"WSLC is the Windows Subsystem for Linux Container CLI tool. It enables management and interaction with WSL "