fix(powershell): stop Out-Null swallowing the AVAILABLE_DOCS status lines (#3891)

Test-FileExists / Test-DirHasFiles report their line with Write-Output and
ALSO return $true/$false — both on the Success stream. The callers piped
the whole call to `| Out-Null` to discard the boolean, which discarded the
report line with it, so text mode printed the header and nothing under it:

  BEFORE (measured, powershell.exe -NoProfile -File ... -IncludeTasks):
    FEATURE_DIR:...\specs\001-f
    AVAILABLE_DOCS:
    (2 lines)

  AFTER:
    FEATURE_DIR:...\specs\001-f
    AVAILABLE_DOCS:
      [OK] research.md
      [FAIL] data-model.md
      [FAIL] contracts/
      [FAIL] quickstart.md
      [FAIL] tasks.md
    (7 lines)

The bash and Python twins both list every document under that header, so
the PowerShell variant silently returned less information for the same
inputs.

Filter out only the boolean, keeping the report lines. Adds the first
PowerShell text-mode test in this file (every existing PS test is -Json).
File stays ASCII-only (verified 0 non-ASCII bytes).

Co-authored-by: Claude Opus 5 (1M context) <noreply@anthropic.com>

scripts/powershell/check-prerequisites.ps1

@@ -157,13 +157,18 @@ if ($Json) {
     Write-Output "FEATURE_DIR:$($paths.FEATURE_DIR)"
     Write-Output "AVAILABLE_DOCS:"
 
-    # Show status of each potential document
-    Test-FileExists -Path $paths.RESEARCH -Description 'research.md' | Out-Null
-    Test-FileExists -Path $paths.DATA_MODEL -Description 'data-model.md' | Out-Null
-    Test-DirHasFiles -Path $paths.CONTRACTS_DIR -Description 'contracts/' | Out-Null
-    Test-FileExists -Path $paths.QUICKSTART -Description 'quickstart.md' | Out-Null
+    # Show status of each potential document.
+    # These helpers report their line with Write-Output and ALSO return a
+    # bool, both on the Success stream, so 'Out-Null' discarded the report
+    # line along with the return value and left AVAILABLE_DOCS empty. Drop
+    # only the boolean so the per-document lines reach stdout like the
+    # bash and Python twins.
+    Test-FileExists -Path $paths.RESEARCH -Description 'research.md' | Where-Object { $_ -isnot [bool] }
+    Test-FileExists -Path $paths.DATA_MODEL -Description 'data-model.md' | Where-Object { $_ -isnot [bool] }
+    Test-DirHasFiles -Path $paths.CONTRACTS_DIR -Description 'contracts/' | Where-Object { $_ -isnot [bool] }
+    Test-FileExists -Path $paths.QUICKSTART -Description 'quickstart.md' | Where-Object { $_ -isnot [bool] }
 
     if ($IncludeTasks) {
-        Test-FileExists -Path $paths.TASKS -Description 'tasks.md' | Out-Null
+        Test-FileExists -Path $paths.TASKS -Description 'tasks.md' | Where-Object { $_ -isnot [bool] }
     }
 }

tests/test_check_prerequisites_python_parity.py

@@ -564,3 +564,38 @@ class TestGetInvokeSeparatorTolerance:
             "integration_settings": {"droid": {"invoke_separator": "-"}},
         })
         assert common.get_invoke_separator(self._repo(tmp_path, body)) == "-"
+
+
+@pytest.mark.skipif(
+    not (HAS_PWSH or _WINDOWS_POWERSHELL), reason="no PowerShell available"
+)
+def test_powershell_text_output_lists_available_docs(prereq_repo: Path) -> None:
+    """Text mode must print a status line per document, like the twins.
+
+    `Test-FileExists` / `Test-DirHasFiles` report their line with `Write-Output`
+    and ALSO `return $true/$false`, both on the Success stream. The callers piped
+    the whole call to `| Out-Null` to discard the boolean, which discarded the
+    report line too — so `AVAILABLE_DOCS:` was emitted with nothing under it
+    while the bash and Python twins list every document.
+    """
+    feat = prereq_repo / "specs" / "001-my-feature"
+    feat.mkdir(parents=True)
+    (feat / "plan.md").write_text("# plan\n", encoding="utf-8")
+    (feat / "research.md").write_text("# research\n", encoding="utf-8")
+    _write_feature_json(prereq_repo)
+
+    ps = _run(_ps_cmd(prereq_repo, "-IncludeTasks"), prereq_repo)
+
+    assert ps.returncode == 0, ps.stderr
+    assert "AVAILABLE_DOCS:" in ps.stdout
+    for doc in (
+        "research.md",
+        "data-model.md",
+        "contracts/",
+        "quickstart.md",
+        "tasks.md",
+    ):
+        assert doc in ps.stdout, (doc, ps.stdout)
+    # The existing file reports [OK], the missing ones [FAIL].
+    assert "[OK] research.md" in _normalize_status_text(ps.stdout), ps.stdout
+    assert "[FAIL] quickstart.md" in _normalize_status_text(ps.stdout), ps.stdout