Add NoOp email service, /docs shortcut and fix streak timezone bug

Replace nil email service pattern with NoOpEmailService (Null Object)
to eliminate nil pointer panics across all handlers.

Add /docs route as a shortcut to Swagger UI.

Fix streak calculation returning 0 when server timezone differs from
UTC — CreatedAt was not converted to UTC before date extraction.

internal/application/commands/request_password_reset_test.go

@@ -89,6 +89,10 @@ func (m *mockRequestResetEmailService) HealthCheck() error {
 	return nil
 }
 
+func (m *mockRequestResetEmailService) IsEnabled() bool {
+	return true
+}
+
 func TestRequestPasswordResetHandler_Success(t *testing.T) {
 	user := entities.NewUser("test@example.com", "hash")
 	user.ID = "user-123"