Add complete Rails 8.1.1 support

Rails 8.1 introduced several breaking changes that required updates
across routing, testing, and SQL generation:

Routing changes (lib/jsonapi/routing_ext.rb):
- Rails 8.1 changed Scope to not support []= operator
- Resource.new signature changed (removed options parameter)
- Solution: Use @jsonapi_resource_type instance variable to track
  resource type instead of @scope[:jsonapi_resource]
- Updated resource_type_with_module_prefix to check instance variable
- Maintains backward compatibility with Rails 4-8.0

Test compatibility (test/integration/requests/request_test.rb):
- Rails 8.1 has more detailed JSON parse error messages
- Updated test_put_invalid_json to accept multiple error formats
- Now matches: "unexpected token at" OR "expected ... got:" OR "parse error"

SQLite boolean representation (test/unit/active_relation_resource_finder/join_manager_test.rb):
- Rails 8.1+ SQLite now uses TRUE instead of 1 for boolean values
- Updated db_true helper with version check for Rails 8.1+
- Maintains support for older Rails versions (5.x-8.0)

Test results:
- Rails 6.1.7.10: 674/674 tests passing ✓
- Rails 7.0.10: 674/674 tests passing ✓
- Rails 7.1.6: 674/674 tests passing ✓
- Rails 7.2.3: 674/674 tests passing ✓
- Rails 8.0.4: 674/674 tests passing ✓
- Rails 8.1.1: 674/674 tests passing ✓

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: takaokouji

lib/jsonapi/routing_ext.rb

@@ -48,7 +48,7 @@ def jsonapi_resource(*resources, &_block)
 
           resource @resource_type, options do
             # :nocov:
-            if @scope.respond_to? :[]=
+            if @scope.respond_to?(:[]=)
               # Rails 4
               @scope[:jsonapi_resource] = @resource_type
 
@@ -57,14 +57,19 @@ def jsonapi_resource(*resources, &_block)
               else
                 jsonapi_relationships
               end
-            else
-              # Rails 5+
-              # Rails 8.1 changed SingletonResource.new to accept only 3 arguments (removed options)
-              resource_arg = if Rails::VERSION::MAJOR >= 8 && Rails::VERSION::MINOR >= 1
-                SingletonResource.new(@resource_type, api_only?, @scope[:shallow])
+            elsif Rails::VERSION::MAJOR >= 8 && Rails::VERSION::MINOR >= 1
+              # Rails 8.1+
+              # Rails 8.1 changed Scope to not support []= and Resource.new signature
+              # Use instance variable to track resource type
+              @jsonapi_resource_type = @resource_type
+              if block_given?
+                yield
               else
-                SingletonResource.new(@resource_type, api_only?, @scope[:shallow], options)
+                jsonapi_relationships
               end
+            else
+              # Rails 5-8.0
+              resource_arg = SingletonResource.new(@resource_type, api_only?, @scope[:shallow], options)
 
               jsonapi_resource_scope(resource_arg, @resource_type) do
                 if block_given?
@@ -130,22 +135,27 @@ def jsonapi_resources(*resources, &_block)
 
           resources @resource_type, options do
             # :nocov:
-            if @scope.respond_to? :[]=
+            if @scope.respond_to?(:[]=)
               # Rails 4
               @scope[:jsonapi_resource] = @resource_type
               if block_given?
                 yield
               else
                 jsonapi_relationships
               end
-            else
-              # Rails 5+
-              # Rails 8.1 changed Resource.new to accept only 3 arguments (removed options)
-              resource_arg = if Rails::VERSION::MAJOR >= 8 && Rails::VERSION::MINOR >= 1
-                Resource.new(@resource_type, api_only?, @scope[:shallow])
+            elsif Rails::VERSION::MAJOR >= 8 && Rails::VERSION::MINOR >= 1
+              # Rails 8.1+
+              # Rails 8.1 changed Scope to not support []= and Resource.new signature
+              # Use instance variable to track resource type
+              @jsonapi_resource_type = @resource_type
+              if block_given?
+                yield
               else
-                Resource.new(@resource_type, api_only?, @scope[:shallow], options)
+                jsonapi_relationships
               end
+            else
+              # Rails 5-8.0
+              resource_arg = Resource.new(@resource_type, api_only?, @scope[:shallow], options)
 
               jsonapi_resource_scope(resource_arg, @resource_type) do
                 if block_given?
@@ -291,7 +301,7 @@ def jsonapi_resource_scope(resource, resource_type) #:nodoc:
         private
 
         def resource_type_with_module_prefix(resource = nil)
-          resource_name = resource || @scope[:jsonapi_resource]
+          resource_name = resource || @scope[:jsonapi_resource] || @jsonapi_resource_type
           [@scope[:module], resource_name].compact.collect(&:to_s).join('/')
         end
       end

test/integration/requests/request_test.rb

@@ -578,7 +578,8 @@ def test_put_invalid_json
 
     assert_equal 400, status
     assert_equal 'Bad Request', json_response['errors'][0]['title']
-    assert_match 'unexpected token at', json_response['errors'][0]['detail']
+    # Rails 8.1+ has more detailed JSON error messages
+    assert_match(/unexpected token at|expected .* got:|parse error/i, json_response['errors'][0]['detail'])
   end
 
   def test_put_valid_json_but_array

test/unit/active_relation_resource_finder/join_manager_test.rb

@@ -6,7 +6,10 @@ class JoinTreeTest < ActiveSupport::TestCase
   def db_true
     case ActiveRecord::Base.connection.adapter_name
       when 'SQLite'
-        if Rails::VERSION::MAJOR >= 6 || (Rails::VERSION::MAJOR >= 5 && ActiveRecord::VERSION::MINOR >= 2)
+        if Rails::VERSION::MAJOR >= 8 && Rails::VERSION::MINOR >= 1
+          # Rails 8.1+ SQLite uses TRUE instead of 1
+          "TRUE"
+        elsif Rails::VERSION::MAJOR >= 6 || (Rails::VERSION::MAJOR >= 5 && ActiveRecord::VERSION::MINOR >= 2)
           "1"
         else
           "'t'"