feat: [DeveloperKnowledge] add AnswerQuery RPC to v1

* feat: add AnswerQuery RPC to v1
docs: Update `DocumentView.DOCUMENT_VIEW_BASIC` comment to include `content_length_bytes`
docs: Update `SearchDocumentChunksRequest.page_size` comment to reflect new maximum limit of 100 and coercion behavior
docs: Update `SearchDocumentChunksRequest.filter` comment to document `content_length_bytes` filtering
docs: Fix formatting in `BatchGetDocumentsRequest.names` comment

The AnswerQuery RPC is now generally available in the v1 API. This method allows clients to submit queries and receive answers grounded in the Developer Knowledge corpus.

PiperOrigin-RevId: 949549664

Source-Link: googleapis/googleapis@6145fa8

Source-Link: https://github.com/googleapis/googleapis-gen/commit/d83f7ceea5d28d83d314e1454f89550c1902b0e6
Copy-Tag: eyJwIjoiRGV2ZWxvcGVyS25vd2xlZGdlLy5Pd2xCb3QueWFtbCIsImgiOiJkODNmN2NlZWE1ZDI4ZDgzZDMxNGUxNDU0Zjg5NTUwYzE5MDJiMGU2In0=

* 🦉 Updates from OwlBot post-processor

See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md

---------

Co-authored-by: Owl Bot <gcf-owl-bot[bot]@users.noreply.github.com>

Author: gcf-owl-bot[bot]

DeveloperKnowledge/metadata/V1/Developerknowledge.php

@@ -0,0 +1,70 @@
+<?php
+/*
+ * Copyright 2026 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * GENERATED CODE WARNING
+ * This file was automatically generated - do not edit!
+ */
+
+require_once __DIR__ . '/../../../vendor/autoload.php';
+
+// [START developerknowledge_v1_generated_DeveloperKnowledge_AnswerQuery_sync]
+use Google\ApiCore\ApiException;
+use Google\Developers\DeveloperKnowledge\V1\AnswerQueryRequest;
+use Google\Developers\DeveloperKnowledge\V1\AnswerQueryResponse;
+use Google\Developers\DeveloperKnowledge\V1\Client\DeveloperKnowledgeClient;
+
+/**
+ * Answers a query using grounded generation.
+ *
+ * @param string $query The query to answer.
+ */
+function answer_query_sample(string $query): void
+{
+    // Create a client.
+    $developerKnowledgeClient = new DeveloperKnowledgeClient();
+
+    // Prepare the request message.
+    $request = (new AnswerQueryRequest())
+        ->setQuery($query);
+
+    // Call the API and handle any network failures.
+    try {
+        /** @var AnswerQueryResponse $response */
+        $response = $developerKnowledgeClient->answerQuery($request);
+        printf('Response data: %s' . PHP_EOL, $response->serializeToJsonString());
+    } catch (ApiException $ex) {
+        printf('Call failed with message: %s' . PHP_EOL, $ex->getMessage());
+    }
+}
+
+/**
+ * Helper to execute the sample.
+ *
+ * This sample has been automatically generated and should be regarded as a code
+ * template only. It will require modifications to work:
+ *  - It may require correct/in-range values for request initialization.
+ *  - It may require specifying regional endpoints when creating the service client,
+ *    please see the apiEndpoint client configuration option for more details.
+ */
+function callSample(): void
+{
+    $query = '[QUERY]';
+
+    answer_query_sample($query);
+}
+// [END developerknowledge_v1_generated_DeveloperKnowledge_AnswerQuery_sync]

DeveloperKnowledge/samples/V1/DeveloperKnowledgeClient/answer_query.php

@@ -37,6 +37,7 @@
  *
  *                                      Format: `documents/{uri_without_scheme}`
  *                                      Example: `documents/docs.cloud.google.com/storage/docs/creating-buckets`
+ *
  *                                      Please see {@see DeveloperKnowledgeClient::documentName()} for help formatting this field.
  */
 function batch_get_documents_sample(string $formattedNamesElement): void