feat(vault): add VaultStore for managing Obsidian-compatible markdown notes

pkg/vault/store.go

@@ -0,0 +1,28 @@
+package vault
+
+import (
+	"os"
+	"path/filepath"
+	"gopkg.in/yaml.v3"
+)
+
+type VaultStore struct {
+	rootPath string
+}
+
+func NewVaultStore(rootPath string) *VaultStore {
+	return &VaultStore{rootPath: rootPath}
+}
+
+func (vs *VaultStore) CreateNote(name string, frontmatter map[string]interface{}, content string) error {
+	if err := os.MkdirAll(vs.rootPath, 0755); err != nil {
+		return err
+	}
+	note := "---\n"
+	if fm, err := yaml.Marshal(frontmatter); err == nil {
+		note += string(fm)
+	}
+	note += "---\n\n" + content
+	notePath := filepath.Join(vs.rootPath, name+".md")
+	return os.WriteFile(notePath, []byte(note), 0644)
+}

pkg/vault/store_test.go

@@ -0,0 +1,62 @@
+package vault
+
+import (
+	"testing"
+	"path/filepath"
+	"os"
+)
+
+func TestCreateNote(t *testing.T) {
+	tmpDir, _ := os.MkdirTemp("", "test-vault")
+	defer os.RemoveAll(tmpDir)
+
+	store := NewVaultStore(tmpDir)
+	
+	err := store.CreateNote("test-note", map[string]interface{}{
+		"title": "Test Note",
+		"tags":  []string{"memory", "test"},
+	}, "## Content here")
+	
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+
+	notePath := filepath.Join(tmpDir, "test-note.md")
+	if _, err := os.Stat(notePath); os.IsNotExist(err) {
+		t.Errorf("expected note file to be created at %s", notePath)
+	}
+}
+
+func TestReadNoteWithFrontmatter(t *testing.T) {
+	store := NewVaultStore("/tmp/test-vault")
+	
+	// Create note with frontmatter
+	store.CreateNote("MEMORY", map[string]interface{}{
+		"title": "Agent Memory",
+		"tags":  []string{"memory"},
+	}, "# Content")
+	
+	fm, body, err := store.ReadNote("MEMORY")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if fm["title"] != "Agent Memory" {
+		t.Errorf("expected title in frontmatter")
+	}
+	if !contains(body, "# Content") {
+		t.Errorf("expected body to contain content")
+	}
+}
+
+func contains(s, substr string) bool {
+	return len(s) >= len(substr) && (s == substr || len(s) > 0 && containsHelper(s, substr))
+}
+
+func containsHelper(s, substr string) bool {
+	for i := 0; i <= len(s)-len(substr); i++ {
+		if s[i:i+len(substr)] == substr {
+			return true
+		}
+	}
+	return false
+}