Add partial Rails 8.1.1 support (664/674 tests passing)

Fix Rails 8.1 routing API breaking changes for Resource and
SingletonResource initialization.

Key Changes:

1. Routing API Update (Rails 8.1):
   - Rails 8.1 changed Resource.new and SingletonResource.new signatures
   - Removed 4th parameter (options) from both constructors
   - Updated signatures:
     * Before: Resource.new(type, api_only, shallow, options)
     * After:  Resource.new(type, api_only, shallow)
   - Add version-conditional logic in routing_ext.rb:
     * Rails 8.1+: Use 3-argument constructor
     * Rails < 8.1: Use 4-argument constructor

Files Modified:
- lib/jsonapi/routing_ext.rb:
  * Fixed Resource.new call (line ~138)
  * Fixed SingletonResource.new call (line ~64)

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: ⚠️ 664/674 tests passing (10 failures)

Rails 8.1 Remaining Issues (10 test failures):
1. JoinTreeTest: SQL generation issue (1 failure)
2. RequestTest: Relationship route 404 errors (5 failures)
3. RequestTest: JSON parse error message format change (4 failures)

All backward compatibility maintained for Rails 6.1-8.0.
Rails 8.1 is partially supported pending investigation of remaining failures.

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

Co-Authored-By: Claude <[email protected]>

Author: takaokouji

lib/jsonapi/routing_ext.rb

@@ -58,8 +58,15 @@ def jsonapi_resource(*resources, &_block)
                 jsonapi_relationships
               end
             else
-              # Rails 5
-              jsonapi_resource_scope(SingletonResource.new(@resource_type, api_only?, @scope[:shallow], options), @resource_type) do
+              # 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])
+              else
+                SingletonResource.new(@resource_type, api_only?, @scope[:shallow], options)
+              end
+
+              jsonapi_resource_scope(resource_arg, @resource_type) do
                 if block_given?
                   yield
                 else
@@ -132,8 +139,15 @@ def jsonapi_resources(*resources, &_block)
                 jsonapi_relationships
               end
             else
-              # Rails 5
-              jsonapi_resource_scope(Resource.new(@resource_type, api_only?, @scope[:shallow], options), @resource_type) do
+              # 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])
+              else
+                Resource.new(@resource_type, api_only?, @scope[:shallow], options)
+              end
+
+              jsonapi_resource_scope(resource_arg, @resource_type) do
                 if block_given?
                   yield
                 else