Steps 10 & 11: Garden accessors and proto-manifest conversion.

Step 10: GetManifest, BlobExists, ReadBlob, WriteBlob, ReplaceManifest
accessor methods on Garden. 5 tests.

Step 11: ManifestToProto/ProtoToManifest conversion functions in
server package with time.Time <-> timestamppb handling. Round-trip
test covering all 3 entry types.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

server/convert_test.go

@@ -0,0 +1,124 @@
+package server
+
+import (
+	"testing"
+	"time"
+
+	"github.com/kisom/sgard/manifest"
+)
+
+func TestManifestRoundTrip(t *testing.T) {
+	now := time.Date(2026, 1, 1, 12, 0, 0, 0, time.UTC)
+	m := &manifest.Manifest{
+		Version: 1,
+		Created: now,
+		Updated: now,
+		Message: "test checkpoint",
+		Files: []manifest.Entry{
+			{Path: "~/.bashrc", Hash: "abcd1234abcd1234abcd1234abcd1234abcd1234abcd1234abcd1234abcd1234", Type: "file", Mode: "0644", Updated: now},
+			{Path: "~/.config/nvim", Type: "directory", Mode: "0755", Updated: now},
+			{Path: "~/.vimrc", Type: "link", Target: "~/.config/nvim/init.vim", Updated: now},
+		},
+	}
+
+	proto := ManifestToProto(m)
+	back := ProtoToManifest(proto)
+
+	if back.Version != m.Version {
+		t.Errorf("Version: got %d, want %d", back.Version, m.Version)
+	}
+	if !back.Created.Equal(m.Created) {
+		t.Errorf("Created: got %v, want %v", back.Created, m.Created)
+	}
+	if !back.Updated.Equal(m.Updated) {
+		t.Errorf("Updated: got %v, want %v", back.Updated, m.Updated)
+	}
+	if back.Message != m.Message {
+		t.Errorf("Message: got %q, want %q", back.Message, m.Message)
+	}
+	if len(back.Files) != len(m.Files) {
+		t.Fatalf("Files count: got %d, want %d", len(back.Files), len(m.Files))
+	}
+	for i, want := range m.Files {
+		got := back.Files[i]
+		if got.Path != want.Path {
+			t.Errorf("Files[%d].Path: got %q, want %q", i, got.Path, want.Path)
+		}
+		if got.Hash != want.Hash {
+			t.Errorf("Files[%d].Hash: got %q, want %q", i, got.Hash, want.Hash)
+		}
+		if got.Type != want.Type {
+			t.Errorf("Files[%d].Type: got %q, want %q", i, got.Type, want.Type)
+		}
+		if got.Mode != want.Mode {
+			t.Errorf("Files[%d].Mode: got %q, want %q", i, got.Mode, want.Mode)
+		}
+		if got.Target != want.Target {
+			t.Errorf("Files[%d].Target: got %q, want %q", i, got.Target, want.Target)
+		}
+		if !got.Updated.Equal(want.Updated) {
+			t.Errorf("Files[%d].Updated: got %v, want %v", i, got.Updated, want.Updated)
+		}
+	}
+}
+
+func TestEmptyManifestRoundTrip(t *testing.T) {
+	now := time.Date(2026, 6, 15, 8, 30, 0, 0, time.UTC)
+	m := &manifest.Manifest{
+		Version: 1,
+		Created: now,
+		Updated: now,
+		Files:   []manifest.Entry{},
+	}
+
+	proto := ManifestToProto(m)
+	back := ProtoToManifest(proto)
+
+	if back.Version != m.Version {
+		t.Errorf("Version: got %d, want %d", back.Version, m.Version)
+	}
+	if !back.Created.Equal(m.Created) {
+		t.Errorf("Created: got %v, want %v", back.Created, m.Created)
+	}
+	if !back.Updated.Equal(m.Updated) {
+		t.Errorf("Updated: got %v, want %v", back.Updated, m.Updated)
+	}
+	if back.Message != "" {
+		t.Errorf("Message: got %q, want empty", back.Message)
+	}
+	if len(back.Files) != 0 {
+		t.Errorf("Files count: got %d, want 0", len(back.Files))
+	}
+}
+
+func TestEntryEmptyOptionalFieldsRoundTrip(t *testing.T) {
+	now := time.Date(2026, 3, 1, 0, 0, 0, 0, time.UTC)
+	e := manifest.Entry{
+		Path:    "~/.profile",
+		Type:    "file",
+		Updated: now,
+		// Hash, Mode, Target intentionally empty
+	}
+
+	proto := EntryToProto(e)
+	back := ProtoToEntry(proto)
+
+	if back.Path != e.Path {
+		t.Errorf("Path: got %q, want %q", back.Path, e.Path)
+	}
+	if back.Hash != "" {
+		t.Errorf("Hash: got %q, want empty", back.Hash)
+	}
+	if back.Type != e.Type {
+		t.Errorf("Type: got %q, want %q", back.Type, e.Type)
+	}
+	if back.Mode != "" {
+		t.Errorf("Mode: got %q, want empty", back.Mode)
+	}
+	if back.Target != "" {
+		t.Errorf("Target: got %q, want empty", back.Target)
+	}
+	if !back.Updated.Equal(e.Updated) {
+		t.Errorf("Updated: got %v, want %v", back.Updated, e.Updated)
+	}
+}