test(apply): cover symlinks, force, dry-run, merge, errors, state round-trip

internal/canonical/load.go

@@ -31,7 +31,10 @@ func Load(root string) (*Bundle, error) {
 	profPath := filepath.Join(root, "profiles", b.Config.ActiveProfile+".yaml")
 	err = loadYAML(profPath, &b.Profile)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("profile %q: %w", b.Config.ActiveProfile, err)
+	}
+	if b.Profile.Name == "" {
+		return nil, fmt.Errorf("profile %q (%s): name is required (expected key 'name' with a string value)", b.Config.ActiveProfile, profPath)
 	}
 
 	mcpPath := filepath.Join(root, "mcp.yaml")
@@ -152,7 +155,7 @@ func loadYAML(path string, out interface{}) error {
 		return fmt.Errorf("read %s: %w", path, err)
 	}
 	if err := yaml.Unmarshal(b, out); err != nil {
-		return fmt.Errorf("parse %s: %w", path, err)
+		return fmt.Errorf("parse %s: %w (check YAML syntax and field names)", path, err)
 	}
 	return nil
 }

internal/canonical/load_test.go

@@ -33,3 +33,31 @@ func TestLoadMissingProfile(t *testing.T) {
 	_, err := Load("testdata/missing")
 	assert.Error(t, err)
 }
+func TestLoadMissingConfigYAML(t *testing.T) {
+	// testdata/missing_config has no config.yaml — only an empty profiles dir.
+	_, err := Load("testdata/missing_config")
+	require.Error(t, err)
+	assert.Contains(t, err.Error(), "config.yaml")
+}
+
+func TestLoadMalformedConfigYAML(t *testing.T) {
+	_, err := Load("testdata/malformed_config")
+	require.Error(t, err)
+	assert.Contains(t, err.Error(), "parse")
+	assert.Contains(t, err.Error(), "config.yaml")
+}
+
+func TestLoadMissingActiveProfile(t *testing.T) {
+	// config.yaml references "nonexistent" profile which has no file.
+	_, err := Load("testdata/missing_active_profile")
+	require.Error(t, err)
+	assert.Contains(t, err.Error(), "nonexistent")
+}
+
+func TestLoadProfileMissingName(t *testing.T) {
+	// profile YAML exists but has no 'name' field.
+	_, err := Load("testdata/profile_no_name")
+	require.Error(t, err)
+	assert.Contains(t, err.Error(), "profile")
+	assert.Contains(t, err.Error(), "name")
+}