[kotlin-spring] Add sealed class polymorphism support

docs/generators/kotlin-spring.md

@@ -34,6 +34,7 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |documentationProvider|Select the OpenAPI documentation provider.|<dl><dt>**none**</dt><dd>Do not publish an OpenAPI specification.</dd><dt>**source**</dt><dd>Publish the original input OpenAPI specification.</dd><dt>**springdoc**</dt><dd>Generate an OpenAPI 3 specification using SpringDoc.</dd></dl>|springdoc|
 |enumPropertyNaming|Naming convention for enum properties: 'camelCase', 'PascalCase', 'snake_case', 'UPPERCASE', and 'original'| |original|
 |exceptionHandler|generate default global exception handlers (not compatible with reactive. enabling reactive will disable exceptionHandler )| |true|
+|fixJacksonJsonTypeInfoInheritance|Only applies when useSealedDiscriminatorClasses is true. When true (default), ensures Jackson polymorphism works correctly by: (1) always setting visible=true on @JsonTypeInfo, and (2) adding the discriminator property to child models with appropriate default values. When false, visible is only set to true if all children already define the discriminator property.| |true|
 |gradleBuildFile|generate a gradle build file using the Kotlin DSL| |true|
 |groupId|Generated artifact package's organization (i.e. maven groupId).| |org.openapitools|
 |includeHttpRequestContext|Whether to include HttpServletRequest (blocking) or ServerWebExchange (reactive) as additional parameter in generated methods.| |false|
@@ -61,6 +62,7 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |useFlowForArrayReturnType|Whether to use Flow for array/collection return types when reactive is enabled. If false, will use List instead.| |true|
 |useJackson3|Use Jackson 3 dependencies (tools.jackson package). Only available with `useSpringBoot4`. Defaults to true when `useSpringBoot4` is enabled. Incompatible with `openApiNullable`.| |false|
 |useResponseEntity|Whether (when false) to return actual type (e.g. List&lt;Fruit&gt;) and handle non-happy path responses via exceptions flow or (when true) return entire ResponseEntity (e.g. ResponseEntity&lt;List&lt;Fruit&gt;&gt;). If disabled, method are annotated using a @ResponseStatus annotation, which has the status of the first response declared in the Api definition| |true|
+|useSealedDiscriminatorClasses|Generate sealed classes instead of interfaces for discriminator models. When true, discriminator parent models are generated as sealed classes with proper Jackson @JsonTypeInfo/@JsonSubTypes annotations and child classes extend the parent with constructor inheritance. When false (default), the legacy interface-based polymorphism is used.| |false|
 |useSealedResponseInterfaces|Generate sealed interfaces for endpoint responses that all possible response types implement. Allows controllers to return any valid response type in a type-safe manner (e.g., sealed interface CreateUserResponse implemented by User, ConflictResponse, ErrorResponse)| |false|
 |useSpringBoot3|Generate code and provide dependencies for use with Spring Boot &ge; 3 (use jakarta instead of javax in imports). Enabling this option will also enable `useJakartaEe`.| |false|
 |useSpringBoot4|Generate code and provide dependencies for use with Spring Boot 4.x. Enabling this option will also enable `useJakartaEe`.| |false|
@@ -307,9 +309,9 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |Composite|✓|OAS2,OAS3
 |Polymorphism|✓|OAS2,OAS3
 |Union|✗|OAS3
-|allOf|✗|OAS2,OAS3
+|allOf|✓|OAS2,OAS3
 |anyOf|✗|OAS3
-|oneOf|✗|OAS3
+|oneOf|✓|OAS3
 |not|✗|OAS3
 
 ### Security Feature