feat: add SHOW LANGUAGES command and QUAL005 missing translations linter rule

SHOW LANGUAGES lists all languages found in the project's translatable
strings with counts, useful for translation workflows:

  mdl> SHOW LANGUAGES;
  | Language   | Strings |
  |------------|---------|
  | en_US      |     142 |
  | nl_NL      |      87 |

QUAL005 (MissingTranslations) linter rule detects elements that have
translations in some languages but not all languages used in the
project:

  [QUAL005] Missing 'nl_NL' translation for PAGE MyModule.EditCustomer
            (page_title: "Edit Customer")

Both features build on the Language column added to the catalog strings
table in the previous commit.

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

Author: ako

mdl/ast/ast_query.go

@@ -84,6 +84,7 @@ const (
 	ShowContractActions      // SHOW CONTRACT ACTIONS FROM Module.Service
 	ShowContractChannels     // SHOW CONTRACT CHANNELS FROM Module.Service (AsyncAPI)
 	ShowContractMessages     // SHOW CONTRACT MESSAGES FROM Module.Service (AsyncAPI)
+	ShowLanguages            // SHOW LANGUAGES
 )
 
 // String returns the human-readable name of the show object type.
@@ -199,6 +200,8 @@ func (t ShowObjectType) String() string {
 		return "CONTRACT CHANNELS"
 	case ShowContractMessages:
 		return "CONTRACT MESSAGES"
+	case ShowLanguages:
+		return "LANGUAGES"
 	default:
 		return "UNKNOWN"
 	}

mdl/executor/cmd_languages.go

@@ -0,0 +1,49 @@
+// SPDX-License-Identifier: Apache-2.0
+
+package executor
+
+import (
+	"fmt"
+)
+
+// showLanguages lists all languages found in the project's translatable strings.
+// Requires REFRESH CATALOG FULL to populate the strings table.
+func (e *Executor) showLanguages() error {
+	if e.catalog == nil {
+		return fmt.Errorf("no catalog available — run REFRESH CATALOG FULL first")
+	}
+
+	result, err := e.catalog.Query(`
+		SELECT Language, COUNT(*) as StringCount
+		FROM strings
+		WHERE Language != ''
+		GROUP BY Language
+		ORDER BY StringCount DESC
+	`)
+	if err != nil {
+		return fmt.Errorf("failed to query languages: %w", err)
+	}
+
+	if len(result.Rows) == 0 {
+		fmt.Fprintln(e.output, "No translatable strings found. Run REFRESH CATALOG FULL to populate the strings table.")
+		return nil
+	}
+
+	// Print table
+	fmt.Fprintf(e.output, "| %-10s | %s |\n", "Language", "Strings")
+	fmt.Fprintf(e.output, "|%-12s|%s|\n", "------------", "---------")
+	for _, row := range result.Rows {
+		lang := ""
+		count := ""
+		if len(row) > 0 {
+			lang = fmt.Sprintf("%v", row[0])
+		}
+		if len(row) > 1 {
+			count = fmt.Sprintf("%v", row[1])
+		}
+		fmt.Fprintf(e.output, "| %-10s | %7s |\n", lang, count)
+	}
+
+	fmt.Fprintf(e.output, "\n(%d languages)\n", len(result.Rows))
+	return nil
+}

mdl/executor/cmd_lint.go

@@ -56,6 +56,7 @@ func (e *Executor) execLint(s *ast.LintStmt) error {
 	lint.AddRule(rules.NewDomainModelSizeRule())
 	lint.AddRule(rules.NewValidationFeedbackRule())
 	lint.AddRule(rules.NewImageSourceRule())
+	lint.AddRule(rules.NewMissingTranslationsRule())
 
 	// Load custom Starlark rules
 	rulesDir := filepath.Join(projectDir, ".claude", "lint-rules")
@@ -122,6 +123,7 @@ func (e *Executor) showLintRules() error {
 	lint.AddRule(rules.NewDomainModelSizeRule())
 	lint.AddRule(rules.NewValidationFeedbackRule())
 	lint.AddRule(rules.NewImageSourceRule())
+	lint.AddRule(rules.NewMissingTranslationsRule())
 
 	for _, rule := range lint.Rules() {
 		fmt.Fprintf(e.output, "  %s (%s)\n", rule.ID(), rule.Name())

mdl/executor/executor.go

@@ -786,6 +786,8 @@ func (e *Executor) execShow(s *ast.ShowStmt) error {
 		return e.showRestClients(s.InModule)
 	case ast.ShowPublishedRestServices:
 		return e.showPublishedRestServices(s.InModule)
+	case ast.ShowLanguages:
+		return e.showLanguages()
 	case ast.ShowContractEntities:
 		return e.showContractEntities(s.Name)
 	case ast.ShowContractActions:

mdl/grammar/MDLLexer.g4

@@ -513,6 +513,7 @@ CONNECTIONS: C O N N E C T I O N S;
 DEFINE: D E F I N E;
 FRAGMENT: F R A G M E N T;
 FRAGMENTS: F R A G M E N T S;
+LANGUAGES: L A N G U A G E S;
 
 // ALTER PAGE keywords
 INSERT: I N S E R T;

mdl/grammar/MDLParser.g4

@@ -2539,6 +2539,7 @@ showStatement
     | SHOW DATABASE CONNECTIONS (IN (qualifiedName | IDENTIFIER))?  // SHOW DATABASE CONNECTIONS [IN module]
     | SHOW REST CLIENTS (IN (qualifiedName | IDENTIFIER))?           // SHOW REST CLIENTS [IN module]
     | SHOW PUBLISHED REST SERVICES (IN (qualifiedName | IDENTIFIER))? // SHOW PUBLISHED REST SERVICES [IN module]
+    | SHOW LANGUAGES                                                 // SHOW LANGUAGES
     ;
 
 /**