Refactor session store configuration; add session method to retrieve store and ensure proper setup

Author: eliasjpr

spec/spec_helper.cr

@@ -22,12 +22,7 @@ class UserSession < Session::Base
   property username : String? = "example"
 end
 
-# Crystal 1.19+ needs a concrete type for @store since the library
-# declares `property store = nil` (no type annotation).
-# Provide the type so specs compile.
-class Session::Configuration
-  @store : Session::MemoryStore(UserSession)? = nil
-end
+Session.use_store(Session::MemoryStore(UserSession))
 
 # Reset configuration to defaults before each test
 def reset_config

src/session.cr

@@ -125,6 +125,10 @@ module Session
   macro use_store(store_type)
     class Session::Configuration
       property store : {{store_type}}? = nil
+
+      def session : {{store_type}}
+        @store || raise "Session store not configured. Call Session.configure and set c.store before using Session.session."
+      end
     end
   end