feat: release configurable API response contracts

Define reusable response bodies in .api with typed code mappings, per-route overrides and matching OpenAPI schemas. Add application and callback encoders, early response policy selection, and isolated remote-consumer release verification.

Release v0.8.0-preview after full race, vet, build and local MySQL workflow acceptance.

openapi/openapi.go

@@ -7,6 +7,7 @@ import (
 	"errors"
 	"fmt"
 	"git.yuntuo.hk/k2safe/go-omni/httpx"
+	"git.yuntuo.hk/k2safe/go-omni/response"
 	"net/http"
 	"reflect"
 	"regexp"
@@ -36,6 +37,7 @@ type Schema struct {
 	Enum                        []any              `json:"enum,omitempty"`
 	Default                     any                `json:"default,omitempty"`
 	Not                         *Schema            `json:"not,omitempty"`
+	AnyOf                       []*Schema          `json:"anyOf,omitempty"`
 }
 type Parameter struct {
 	Name        string  `json:"name"`
@@ -181,7 +183,8 @@ func (a *API) Handler() httpx.Handler {
 	}
 }
 func Envelope(data *Schema) *Schema {
-	return &Schema{Type: "object", Required: []string{"code", "message"}, Properties: map[string]*Schema{"code": {Type: "string"}, "message": {Type: "string"}, "requestId": {Type: "string"}, "data": data}}
+	schema, _ := EnvelopeWith(data, response.Config{})
+	return schema
 }
 func SchemaOf[T any]() (*Schema, error) {
 	return schema(reflect.TypeOf((*T)(nil)).Elem(), map[reflect.Type]bool{}, 0)