fix(api): 补全模型能力继承与响应推导

- 合并 base model 默认能力与平台覆盖项
- 在模型响应中补齐 text_generate 的上下文与推理能力字段
- 为相关逻辑补充测试和迁移脚本

apps/api/internal/store/platform_models.go

@@ -30,6 +30,13 @@ func (s *Store) CreatePlatformModel(ctx context.Context, input CreatePlatformMod
 	return s.createPlatformModel(ctx, s.pool, input)
 }
 
+// EffectivePlatformModelCapabilities merges base defaults with platform overrides.
+// Nested capability objects are merged recursively so platform fields override
+// only the same nested keys while preserving other base capability defaults.
+func EffectivePlatformModelCapabilities(base map[string]any, override map[string]any) map[string]any {
+	return mergeCapabilityObjects(base, override)
+}
+
 func (s *Store) ReplacePlatformModels(ctx context.Context, platformID string, inputs []CreatePlatformModelInput) ([]PlatformModel, error) {
 	tx, err := s.pool.Begin(ctx)
 	if err != nil {
@@ -107,7 +114,7 @@ func (s *Store) createPlatformModel(ctx context.Context, q platformModelQuerier,
 	}
 	capabilities := input.Capabilities
 	if len(capabilities) == 0 {
-		capabilities = mergeObjects(base.Capabilities, input.CapabilityOverride)
+		capabilities = EffectivePlatformModelCapabilities(base.Capabilities, input.CapabilityOverride)
 	}
 	billingConfig := input.BillingConfig
 	if len(billingConfig) == 0 {
@@ -355,6 +362,48 @@ func mergeObjects(base map[string]any, override map[string]any) map[string]any {
 	return out
 }
 
+func mergeCapabilityObjects(base map[string]any, override map[string]any) map[string]any {
+	out := cloneObject(base)
+	for key, value := range override {
+		baseChild, baseOK := out[key].(map[string]any)
+		overrideChild, overrideOK := value.(map[string]any)
+		if baseOK && overrideOK {
+			out[key] = mergeCapabilityObjects(baseChild, overrideChild)
+			continue
+		}
+		out[key] = cloneObjectValue(value)
+	}
+	if len(out) == 0 {
+		return nil
+	}
+	return out
+}
+
+func cloneObject(values map[string]any) map[string]any {
+	out := make(map[string]any, len(values))
+	for key, value := range values {
+		out[key] = cloneObjectValue(value)
+	}
+	return out
+}
+
+func cloneObjectValue(value any) any {
+	switch typed := value.(type) {
+	case map[string]any:
+		return cloneObject(typed)
+	case []any:
+		out := make([]any, 0, len(typed))
+		for _, item := range typed {
+			out = append(out, cloneObjectValue(item))
+		}
+		return out
+	case []string:
+		return append([]string(nil), typed...)
+	default:
+		return value
+	}
+}
+
 func emptyObjectIfNil(value map[string]any) map[string]any {
 	if value == nil {
 		return map[string]any{}