Merge pull request '[agent/claude:opus] DX audit and fix. 1) Review CLAUDE.md — update any outdate...' (#1) from agent/dx-audit-and-fix--1--review-claude-md into main

- Fix RegisterCommands call to match single-arg signature; register
  locales separately via i18n.RegisterLocales
- Replace os.Stat/os.ReadDir with coreio.Local equivalents in
  detect.go, format.go, main.go, cmd_docblock.go
- Add tests for languagesFromRules, IsExcludedDir, ScanFile edge cases
- Coverage: pkg/lint 71.0% → 72.9%, pkg/detect 100%, pkg/php 68.7%

Co-Authored-By: Virgil <virgil@lethean.io>

cmd/core-lint/main.go

@@ -7,6 +7,7 @@ import (
 	"strings"
 
 	"forge.lthn.ai/core/cli/pkg/cli"
+	coreio "forge.lthn.ai/core/go-io"
 	coreerr "forge.lthn.ai/core/go-log"
 	lint "forge.lthn.ai/core/lint"
 	lintpkg "forge.lthn.ai/core/lint/pkg/lint"
@@ -66,7 +67,7 @@ func addLintCommands(root *cli.Command) {
 
 		var allFindings []lintpkg.Finding
 		for _, p := range paths {
-			info, err := os.Stat(p)
+			info, err := coreio.Local.Stat(p)
 			if err != nil {
 				return coreerr.E("cmd.check", "stat "+p, err)
 			}

cmd/qa/cmd_docblock.go

@@ -20,6 +20,7 @@ import (
 	"strings"
 
 	"forge.lthn.ai/core/cli/pkg/cli"
+	coreio "forge.lthn.ai/core/go-io"
 	"forge.lthn.ai/core/go-i18n"
 )
 
@@ -235,7 +236,7 @@ func expandPatterns(patterns []string) ([]string, error) {
 
 // hasGoFiles checks if a directory contains Go files.
 func hasGoFiles(dir string) bool {
-	entries, err := os.ReadDir(dir)
+	entries, err := coreio.Local.List(dir)
 	if err != nil {
 		return false
 	}

cmd/qa/cmd_qa.go

@@ -12,12 +12,13 @@ package qa
 
 import (
 	"forge.lthn.ai/core/cli/pkg/cli"
-	"forge.lthn.ai/core/go-i18n"
+	i18n "forge.lthn.ai/core/go-i18n"
 	"forge.lthn.ai/core/lint/locales"
 )
 
 func init() {
-	cli.RegisterCommands(AddQACommands, locales.FS)
+	i18n.RegisterLocales(locales.FS, ".")
+	cli.RegisterCommands(AddQACommands)
 }
 
 // Style aliases from shared package

pkg/detect/detect.go

@@ -1,7 +1,11 @@
 // Package detect identifies project types by examining filesystem markers.
 package detect
 
-import "os"
+import (
+	"path/filepath"
+
+	coreio "forge.lthn.ai/core/go-io"
+)
 
 // ProjectType identifies a project's language/framework.
 type ProjectType string
@@ -13,14 +17,12 @@ const (
 
 // IsGoProject returns true if dir contains a go.mod file.
 func IsGoProject(dir string) bool {
-	_, err := os.Stat(dir + "/go.mod")
+	return coreio.Local.Exists(filepath.Join(dir, "go.mod"))
-	return err == nil
 }
 
 // IsPHPProject returns true if dir contains a composer.json file.
 func IsPHPProject(dir string) bool {
-	_, err := os.Stat(dir + "/composer.json")
+	return coreio.Local.Exists(filepath.Join(dir, "composer.json"))
-	return err == nil
 }
 
 // DetectAll returns all detected project types in the directory.

pkg/lint/scanner_test.go

@@ -209,6 +209,89 @@ func TestScanDir_Good_Subdirectories(t *testing.T) {
 	require.Len(t, findings, 1)
 }
 
+func TestLanguagesFromRules_Good(t *testing.T) {
+	rules := []Rule{
+		{Languages: []string{"go", "php"}},
+		{Languages: []string{"go", "ts"}},
+		{Languages: []string{"py"}},
+	}
+	langs := languagesFromRules(rules)
+	assert.Equal(t, []string{"go", "php", "py", "ts"}, langs)
+}
+
+func TestLanguagesFromRules_Good_Empty(t *testing.T) {
+	langs := languagesFromRules(nil)
+	assert.Empty(t, langs)
+}
+
+func TestIsExcludedDir_Good(t *testing.T) {
+	tests := []struct {
+		name string
+		want bool
+	}{
+		{"vendor", true},
+		{"node_modules", true},
+		{".git", true},
+		{"testdata", true},
+		{".core", true},
+		{".hidden", true},  // any dot-prefixed dir
+		{".idea", true},    // any dot-prefixed dir
+		{"src", false},
+		{"pkg", false},
+		{"cmd", false},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			assert.Equal(t, tt.want, IsExcludedDir(tt.name))
+		})
+	}
+}
+
+func TestScanFile_Bad_UnrecognisedExtension(t *testing.T) {
+	dir := t.TempDir()
+	file := filepath.Join(dir, "readme.txt")
+	require.NoError(t, os.WriteFile(file, []byte("TODO: fix this"), 0o644))
+
+	rules := []Rule{
+		{
+			ID:        "test-001",
+			Title:     "Found TODO",
+			Severity:  "low",
+			Languages: []string{"go"},
+			Pattern:   `TODO`,
+			Fix:       "Remove TODO",
+			Detection: "regex",
+		},
+	}
+
+	s, err := NewScanner(rules)
+	require.NoError(t, err)
+
+	findings, err := s.ScanFile(file)
+	require.NoError(t, err)
+	assert.Empty(t, findings, "should not match unrecognised extensions")
+}
+
+func TestScanFile_Bad_NonexistentFile(t *testing.T) {
+	rules := []Rule{
+		{
+			ID:        "test-001",
+			Title:     "Test",
+			Severity:  "low",
+			Languages: []string{"go"},
+			Pattern:   `TODO`,
+			Fix:       "Fix",
+			Detection: "regex",
+		},
+	}
+
+	s, err := NewScanner(rules)
+	require.NoError(t, err)
+
+	_, err = s.ScanFile("/nonexistent/test.go")
+	assert.Error(t, err)
+}
+
 func TestScanDir_Bad_NonexistentDir(t *testing.T) {
 	rules := []Rule{
 		{

pkg/php/format.go

@@ -8,13 +8,13 @@ import (
 	"os/exec"
 	"path/filepath"
 
+	coreio "forge.lthn.ai/core/go-io"
 	coreerr "forge.lthn.ai/core/go-log"
 )
 
 // fileExists reports whether the named file or directory exists.
 func fileExists(path string) bool {
-	_, err := os.Stat(path)
+	return coreio.Local.Exists(path)
-	return err == nil
 }
 
 // FormatOptions configures PHP code formatting.