Fixed Anthropic Messages API code samples and switched model-card OpenAI-SDK samples to bedrock-runtime
Fixed the Anthropic Messages API Python sample on the <a href="https://docs.aws.amazon.com/bedrock/latest/userguide/what-is-bedrock.html">Overview</a> page, which previously used <code class="code">anthropic.Anthropic()</code> with no base URL and failed with a validation exception. Every Anthropic Messages API Python sample now uses the plain <code class="code">Anthropic</code> client from the Anthropic SDK, targets the <code class="code">bedrock-runtime</code> endpoint's <code class="code">/anthropic</code> route directly with <code class="code">base_url="https://bedrock-runtime.<span>{</span>region}.amazonaws.com/anthropic"</code>, and authenticates with a short-term Amazon Bedrock bearer token generated by <a href="https://pypi.org/project/aws-bedrock-token-generator/" rel="noopener noreferrer" target="_blank">aws-bedrock-token-generator</a>'s <code class="code">provide_token()</code>. Updated the Sample Code section of every Anthropic model card that supports <code class="code">bedrock-runtime</code> (Claude Opus 5, Opus 4.8, Opus 4.7, Sonnet 5, Haiku 4.5, and Fable 5) to use this pattern with the model's Global inference ID, and updated the corresponding <code class="code">pip install</code> line to <code class="code">pip install -U anthropic aws-bedrock-token-generator</code>. Updated the same sample on the <a href="https://docs.aws.amazon.com/bedrock/latest/userguide/getting-started.html">Quickstart</a> page, the <a href="https://docs.aws.amazon.com/bedrock/latest/userguide/inference-messages-api.html">Messages API</a> topic, and the <a href="https://docs.aws.amazon.com/bedrock/latest/userguide/inference-anthropic-claude-messages-tool-use.html">Tool use</a> reference topic. Reordered the code sample tabs on the Messages API topic to lead with <code class="code">bedrock-runtime</code> variants (Anthropic SDK, boto3, AWS CLI, curl) and moved the <code class="code">bedrock-mantle</code> curl tab to the end. Repointed the <code class="code">OPENAI_BASE_URL</code> environment variable on 49 non-Anthropic model cards (OpenAI, Mistral AI, DeepSeek, Google, Meta, Qwen, MiniMax, NVIDIA, Moonshot AI, Z.AI, Writer, xAI) from the <code class="code">bedrock-mantle</code> <code class="code">/v1</code> route to the <code class="code">bedrock-runtime</code> <code class="code">/openai/v1</code> route (<code class="code">https://bedrock-runtime.<span>{</span>region}.amazonaws.com/openai/v1</code>) so the Responses API and Chat Completions API samples in the Sample Code section run against <code class="code">bedrock-runtime</code> by default. The <code class="code">bedrock-mantle</code> endpoint continues to be fully supported and pages that document mantle-only features (Web Search, Projects, Workspaces, Chat Completions on mantle, the mantle Responses API page) still show <code class="code">bedrock-mantle</code> URLs.