feat(pluginstore): make registry version field optional

The latest release is now the source of truth for plugin versions, so
the registry version only serves as a display fallback. Validate its
format only when present.

internal/pluginstore/registry.go

@@ -94,7 +94,6 @@ func ValidatePlugin(plugin Plugin) error {
 		"name":        plugin.Name,
 		"description": plugin.Description,
 		"author":      plugin.Author,
-		"version":     plugin.Version,
 		"repository":  plugin.Repository,
 	}
 	for field, value := range required {
@@ -105,7 +104,9 @@ func ValidatePlugin(plugin Plugin) error {
 	if !pluginhost.ValidatePluginID(strings.TrimSpace(plugin.ID)) {
 		return fmt.Errorf("invalid plugin id %q", plugin.ID)
 	}
-	if !validPluginVersion(strings.TrimSpace(plugin.Version)) {
+	// The version is optional since the latest release is the source of truth;
+	// when present it is only used as a display fallback and must be valid.
+	if version := strings.TrimSpace(plugin.Version); version != "" && !validPluginVersion(version) {
 		return fmt.Errorf("invalid plugin version %q", plugin.Version)
 	}
 	if _, _, errRepository := GitHubRepositoryParts(plugin.Repository); errRepository != nil {

internal/pluginstore/registry_test.go

@@ -68,6 +68,21 @@ func TestParseRegistryNormalizesPluginFields(t *testing.T) {
 	}
 }
 
+func TestValidateRegistryAllowsMissingVersion(t *testing.T) {
+	t.Parallel()
+
+	registry := Registry{SchemaVersion: 1, Plugins: []Plugin{{
+		ID:          "sample-provider",
+		Name:        "Sample Provider",
+		Description: "Adds sample provider support.",
+		Author:      "author-name",
+		Repository:  "https://github.com/author-name/cliproxy-sample-provider-plugin",
+	}}}
+	if errValidate := ValidateRegistry(registry); errValidate != nil {
+		t.Fatalf("ValidateRegistry() error = %v, want nil for missing version", errValidate)
+	}
+}
+
 func TestValidateRegistryRejectsInvalidEntries(t *testing.T) {
 	t.Parallel()