Skip hidden directories in recursive skill loading

Return fs.SkipDir for hidden directories and symlinks instead of
descending into them. This avoids walking large trees like .git,
.node_modules, or .cache that can never contain skills.

Assisted-By: cagent

Author: dgageot

pkg/skills/skills.go

@@ -194,7 +194,7 @@ func loadSkillsFlat(dir string) []Skill {
 
 	var skills []Skill
 	for _, entry := range entries {
-		if !entry.IsDir() || isHiddenOrSymlink(entry) {
+		if !entry.IsDir() || (isHidden(entry) || isSymlink(entry)) {
 			continue
 		}
 
@@ -214,10 +214,18 @@ func loadSkillsRecursive(dir string) []Skill {
 	var skills []Skill
 
 	_ = filepath.WalkDir(dir, func(path string, d fs.DirEntry, err error) error {
-		if err != nil || d.IsDir() {
+		if err != nil {
 			return nil
 		}
-		if isHiddenOrSymlink(d) || d.Name() != skillFile {
+
+		if d.IsDir() {
+			if path != dir && isHidden(d) {
+				return fs.SkipDir
+			}
+			return nil
+		}
+
+		if d.Name() != skillFile {
 			return nil
 		}
 
@@ -277,17 +285,14 @@ func parseFrontmatter(content string) (Skill, bool) {
 	return skill, true
 }
 
-// isValidSkill validates skill constraints.
 func isValidSkill(skill Skill) bool {
-	// Description and name is required
-	if skill.Description == "" || skill.Name == "" {
-		return false
-	}
+	return skill.Description != "" && skill.Name != ""
+}
 
-	return true
+func isHidden(entry fs.DirEntry) bool {
+	return strings.HasPrefix(entry.Name(), ".")
 }
 
-// isHiddenOrSymlink returns true for hidden files/dirs or symlinks.
-func isHiddenOrSymlink(entry fs.DirEntry) bool {
-	return strings.HasPrefix(entry.Name(), ".") || entry.Type()&os.ModeSymlink != 0
+func isSymlink(entry fs.DirEntry) bool {
+	return entry.Type()&os.ModeSymlink != 0
 }