feat(js): add streaming utility templates for streamedListObjects

Adds NDJSON streaming parser template to support streamedListObjects in
the JavaScript SDK. Templates provide the parsing utility; actual streaming
implementation remains in custom code (client.ts, common.ts) in js-sdk repo.

Templates Added/Modified (5 files):
- streaming.mustache (NEW) - NDJSON parser for Node.js streams
  - Proper error propagation (pending promises reject on error)
  - onEnd guard prevents processing after error state
  - Widened type signature (Readable|AsyncIterable|string|Buffer)
- index.mustache - Export parseNDJSONStream utility
- config.overrides.json - Register streaming.mustache + supportsStreamedListObjects flag
- README_calling_api.mustache - Add Streamed List Objects usage documentation
- README_api_endpoints.mustache - Add endpoint to API table

Architecture:
- Templates generate utilities and basic API methods
- Custom code in js-sdk handles actual streaming (client.ts, common.ts)
- No OpenAPI spec changes required

Tested:
- Generated streaming.ts includes all error handling fixes
- parseNDJSONStream exported correctly
- Custom js-sdk code works with generated utilities

Related:
- Fixes #76 (JavaScript SDK)
- Implements openfga/js-sdk#236
- Related PR: openfga/js-sdk#280

Author: daniel-jonathan

config/clients/js/template/api.mustache

@@ -10,7 +10,6 @@ import {
     serializeDataIfNeeded,
     toPathString,
     createRequestFunction,
-    createStreamingRequestFunction,
     RequestArgs,
     CallResult,
     PromiseResult

config/clients/js/template/apiInner.mustache

@@ -8,7 +8,6 @@ import {
   serializeDataIfNeeded,
   toPathString,
   createRequestFunction,
-  createStreamingRequestFunction,
   CallResult,
   RequestArgs,
   PromiseResult
@@ -210,22 +209,16 @@ export const {{classname}}Fp = function(configuration: Configuration, credential
          * @deprecated{{/isDeprecated}}
          * @throws { FgaError }
          */
-        async {{nickname}}({{#allParams}}{{paramName}}{{^required}}?{{/required}}: {{{dataType}}}, {{/allParams}}options?: any): Promise<(axios?: AxiosInstance) => {{#vendorExtensions}}{{#x-fga-streaming}}Promise<any>{{/x-fga-streaming}}{{^x-fga-streaming}}PromiseResult<{{#returnType}}{{{returnType}}}{{/returnType}}{{^returnType}}void{{/returnType}}>{{/x-fga-streaming}}{{/vendorExtensions}}{{^vendorExtensions}}PromiseResult<{{#returnType}}{{{returnType}}}{{/returnType}}{{^returnType}}void{{/returnType}}>{{/vendorExtensions}}> {
+        async {{nickname}}({{#allParams}}{{paramName}}{{^required}}?{{/required}}: {{{dataType}}}, {{/allParams}}options?: any): Promise<(axios?: AxiosInstance) => PromiseResult<{{#returnType}}{{{returnType}}}{{/returnType}}{{^returnType}}void{{/returnType}}>> {
             const localVarAxiosArgs = localVarAxiosParamCreator.{{nickname}}({{#allParams}}{{paramName}}, {{/allParams}}options);
-            return {{#vendorExtensions}}{{#x-fga-streaming}}createStreamingRequestFunction{{/x-fga-streaming}}{{^x-fga-streaming}}createRequestFunction{{/x-fga-streaming}}{{/vendorExtensions}}{{^vendorExtensions}}createRequestFunction{{/vendorExtensions}}(localVarAxiosArgs, globalAxios, configuration, credentials, {
-                [TelemetryAttribute.FgaClientRequestMethod]: "{{operationIdCamelCase}}"{{#vendorExtensions}}{{^x-fga-streaming}},
+            return createRequestFunction(localVarAxiosArgs, globalAxios, configuration, credentials, {
+                [TelemetryAttribute.FgaClientRequestMethod]: "{{operationIdCamelCase}}",
                 {{#pathParams.0}}
                 [TelemetryAttribute.FgaClientRequestStoreId]: storeId ?? "",
                 {{/pathParams.0}}
                 {{#bodyParam}}
                 ...TelemetryAttributes.fromRequestBody(body)
-                {{/bodyParam}}{{/x-fga-streaming}}{{/vendorExtensions}}{{^vendorExtensions}},
-                {{#pathParams.0}}
-                [TelemetryAttribute.FgaClientRequestStoreId]: storeId ?? "",
-                {{/pathParams.0}}
-                {{#bodyParam}}
-                ...TelemetryAttributes.fromRequestBody(body)
-                {{/bodyParam}}{{/vendorExtensions}}
+                {{/bodyParam}}
             });
         },
     {{/operation}}
@@ -253,7 +246,7 @@ export const {{classname}}Factory = function (configuration: Configuration, cred
          * @deprecated{{/isDeprecated}}
          * @throws { FgaError }
          */
-        {{nickname}}({{#allParams}}{{paramName}}{{^required}}?{{/required}}: {{{dataType}}}, {{/allParams}}options?: any): {{#vendorExtensions}}{{#x-fga-streaming}}Promise<any>{{/x-fga-streaming}}{{^x-fga-streaming}}PromiseResult<{{#returnType}}{{{returnType}}}{{/returnType}}{{^returnType}}void{{/returnType}}>{{/x-fga-streaming}}{{/vendorExtensions}}{{^vendorExtensions}}PromiseResult<{{#returnType}}{{{returnType}}}{{/returnType}}{{^returnType}}void{{/returnType}}>{{/vendorExtensions}} {
+        {{nickname}}({{#allParams}}{{paramName}}{{^required}}?{{/required}}: {{{dataType}}}, {{/allParams}}options?: any): PromiseResult<{{#returnType}}{{{returnType}}}{{/returnType}}{{^returnType}}void{{/returnType}}> {
             return localVarFp.{{nickname}}({{#allParams}}{{paramName}}, {{/allParams}}options).then((request) => request(axios));
         },
     {{/operation}}
@@ -348,12 +341,12 @@ export class {{classname}} extends BaseAPI {
      * @memberof {{classname}}
      */
     {{#useSingleRequestParameter}}
-    public {{nickname}}({{#allParams.0}}requestParameters: {{classname}}{{operationIdCamelCase}}Request{{^hasRequiredParams}} = {}{{/hasRequiredParams}}, {{/allParams.0}}options?: any): {{#vendorExtensions}}{{#x-fga-streaming}}Promise<any>{{/x-fga-streaming}}{{^x-fga-streaming}}Promise<CallResult<{{#returnType}}{{{returnType}}}{{/returnType}}{{^returnType}}void{{/returnType}}>>{{/x-fga-streaming}}{{/vendorExtensions}}{{^vendorExtensions}}Promise<CallResult<{{#returnType}}{{{returnType}}}{{/returnType}}{{^returnType}}void{{/returnType}}>>{{/vendorExtensions}} {
+    public {{nickname}}({{#allParams.0}}requestParameters: {{classname}}{{operationIdCamelCase}}Request{{^hasRequiredParams}} = {}{{/hasRequiredParams}}, {{/allParams.0}}options?: any): Promise<CallResult<{{#returnType}}{{{returnType}}}{{/returnType}}{{^returnType}}void{{/returnType}}>> {
         return {{classname}}Fp(this.configuration, this.credentials).{{nickname}}({{#allParams.0}}{{#allParams}}requestParameters.{{paramName}}, {{/allParams}}{{/allParams.0}}options).then((request) => request(this.axios));
     }
     {{/useSingleRequestParameter}}
     {{^useSingleRequestParameter}}
-    public {{nickname}}({{#allParams}}{{paramName}}{{^required}}?{{/required}}: {{{dataType}}}, {{/allParams}}options?: any): {{#vendorExtensions}}{{#x-fga-streaming}}Promise<any>{{/x-fga-streaming}}{{^x-fga-streaming}}Promise<CallResult<{{#returnType}}{{{returnType}}}{{/returnType}}{{^returnType}}void{{/returnType}}>>{{/x-fga-streaming}}{{/vendorExtensions}}{{^vendorExtensions}}Promise<CallResult<{{#returnType}}{{{returnType}}}{{/returnType}}{{^returnType}}void{{/returnType}}>>{{/vendorExtensions}} {
+    public {{nickname}}({{#allParams}}{{paramName}}{{^required}}?{{/required}}: {{{dataType}}}, {{/allParams}}options?: any): Promise<CallResult<{{#returnType}}{{{returnType}}}{{/returnType}}{{^returnType}}void{{/returnType}}>> {
         return {{classname}}Fp(this.configuration, this.credentials).{{nickname}}({{#allParams}}{{paramName}}, {{/allParams}}options).then((request) => request(this.axios));
     }
     {{/useSingleRequestParameter}}