fix(cmd/mdsmith): address code-review round 1 findings

- Strengthen TestRunCheck_Stdin_ChecksSource and
  TestRunCheck_Discovered_ChecksConfiguredFiles: both fed clean
  Markdown and asserted only exit code 0, which a silent
  stdin-routing or discovery bug could also produce. Switch to
  content with a trailing-space diagnostic and assert exit code 1
  plus the diagnostic source.
- Close the pipe read end in TestRunCheck_Stdin_ChecksSource,
  matching the close-both-ends convention used elsewhere in this
  file.
- Correct the touched-file count in the audit log (148, not 134 —
  two-dot diff --stat is the accurate count) and the internal/githooks
  line count cited in plan/2608021916 (1,346, not 1,347).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016AbFuwvqqq2fBiYWa3ubap

Author: claude

cmd/mdsmith/main_unit_test.go

@@ -836,18 +836,22 @@ func TestRunCheck_Stdin_ChecksSource(t *testing.T) {
 	oldStdin := os.Stdin
 	r, w, err := os.Pipe()
 	require.NoError(t, err)
+	defer r.Close() //nolint:errcheck // best-effort close on read-only pipe end
 	os.Stdin = r
 	defer func() { os.Stdin = oldStdin }()
 	go func() {
-		_, _ = w.WriteString("# Title\n\nContent here.\n")
+		// Trailing spaces trigger a diagnostic, so a passing exit code
+		// alone can't mask a routing bug that skips reading stdin.
+		_, _ = w.WriteString("# Title\n\nHello   \n")
 		_ = w.Close()
 	}()
 
 	var code int
-	captureStderr(func() {
+	stderr := captureStderr(func() {
 		code = runCheck([]string{"-"})
 	})
-	assert.Equal(t, 0, code)
+	assert.Equal(t, 1, code)
+	assert.Contains(t, stderr, "<stdin>")
 }
 
 func TestRunCheck_Files_ExitsOneOnDiagnostics(t *testing.T) {
@@ -868,15 +872,18 @@ func TestRunCheck_Discovered_ChecksConfiguredFiles(t *testing.T) {
 	dir := t.TempDir()
 	require.NoError(t, os.WriteFile(filepath.Join(dir, ".mdsmith.yml"),
 		[]byte("files: [\"**/*.md\"]\n"), 0o644))
+	// Trailing spaces trigger a diagnostic, so a passing exit code alone
+	// can't mask a discovery bug that silently finds zero files.
 	require.NoError(t, os.WriteFile(filepath.Join(dir, "test.md"),
-		[]byte("# Title\n\nContent here.\n"), 0o644))
+		[]byte("# Title\n\nHello   \n"), 0o644))
 	t.Chdir(dir)
 
 	var code int
-	captureStderr(func() {
+	stderr := captureStderr(func() {
 		code = runCheck(nil)
 	})
-	assert.Equal(t, 0, code)
+	assert.Equal(t, 1, code)
+	assert.Contains(t, stderr, "test.md")
 }
 
 // --- runFix ---

docs/development/architecture-audit.md

@@ -19,7 +19,7 @@ every finding there is resolved.
 
 ## Audit 2026-08-02 (range: 6680ff5..2ab4b29)
 
-134 touched files. Notable new surfaces: MDS073
+148 touched files. Notable new surfaces: MDS073
 slide-structure and MDS060 occurrence. MDS073 was
 renamed from MDS072; no leftover duplication was
 found. Also new: foreign-managed regions and

plan/2608021916_arch-fix-githooks-package-split.md

@@ -35,7 +35,7 @@ found this SRP smell:
   refactor-moves section: "Split a package by question.
   If the package doc comment requires 'and' to describe
   ... the package wants to be two."
-- The file is 1,347 lines and cleanly separates into:
+- The file is 1,346 lines and cleanly separates into:
   - hook-script generation/validation
     (`BuildHookScript`, `HookMatchesCanonical`,
     the staging shell-function builder);