feat(license): enforce max_apps at AppService.createApp

Adds CreateGuard hook to AppService.createApp using the same pattern
as T18 (EnvironmentService). AppRepository.count() added; the bean
wires LicenseEnforcer.assertWithinCap("max_apps", current, 1).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

cameleer-server-core/src/main/java/com/cameleer/server/core/runtime/AppRepository.java

@@ -8,6 +8,7 @@ import java.util.UUID;
 public interface AppRepository {
     List<App> findByEnvironmentId(UUID environmentId);
     List<App> findAll();
+    long count();
     Optional<App> findById(UUID id);
     Optional<App> findByEnvironmentIdAndSlug(UUID environmentId, String slug);
     Optional<App> findBySlug(String slug);

cameleer-server-core/src/main/java/com/cameleer/server/core/runtime/AppService.java

@@ -23,11 +23,18 @@ public class AppService {
     private final AppRepository appRepo;
     private final AppVersionRepository versionRepo;
     private final String jarStoragePath;
+    private final CreateGuard createGuard;
 
     public AppService(AppRepository appRepo, AppVersionRepository versionRepo, String jarStoragePath) {
+        this(appRepo, versionRepo, jarStoragePath, CreateGuard.NOOP);
+    }
+
+    public AppService(AppRepository appRepo, AppVersionRepository versionRepo, String jarStoragePath,
+                      CreateGuard createGuard) {
         this.appRepo = appRepo;
         this.versionRepo = versionRepo;
         this.jarStoragePath = jarStoragePath;
+        this.createGuard = createGuard;
     }
 
     public List<App> listAll() { return appRepo.findAll(); }
@@ -55,6 +62,7 @@ public class AppService {
             throw new IllegalArgumentException(
                     "Invalid app slug: must match ^[a-z0-9][a-z0-9-]{0,63}$ (lowercase letters, digits, hyphens)");
         }
+        createGuard.check(appRepo.count());
         if (appRepo.findByEnvironmentIdAndSlug(environmentId, slug).isPresent()) {
             throw new IllegalArgumentException("App with slug '" + slug + "' already exists in this environment");
         }