feat(anthropic): add Claude 4.5 Sonnet model with pricing and token limits

This commit introduces the Claude 4.5 Sonnet model to the Anthropic integration, including its pricing details and token limits. The new model expands the capabilities of the Anthropic offerings.

Author: dosco

src/ax/ai/anthropic/info.ts

@@ -3,6 +3,16 @@ import type { AxModelInfo } from '../types.js';
 import { AxAIAnthropicModel } from './types.js';
 
 export const axModelInfoAnthropic: AxModelInfo[] = [
+  // 4.5 Sonnet (2025-09)
+  {
+    name: AxAIAnthropicModel.Claude45Sonnet,
+    currency: 'usd',
+    // Estimated/prior pricing aligned with Sonnet tier
+    promptTokenCostPer1M: 3.0,
+    completionTokenCostPer1M: 15.0,
+    maxTokens: 200000,
+    supported: { thinkingBudget: true, showThoughts: true },
+  },
   // 4.5 Haiku (2025-10)
   {
     name: AxAIAnthropicModel.Claude45Haiku,

src/ax/ai/anthropic/types.ts

@@ -4,6 +4,7 @@ export enum AxAIAnthropicModel {
   Claude41Opus = 'claude-opus-4-1-20250805',
   Claude4Opus = 'claude-opus-4-20250514',
   Claude4Sonnet = 'claude-sonnet-4-20250514',
+  Claude45Sonnet = 'claude-sonnet-4-5-20250929',
   Claude45Haiku = 'claude-haiku-4-5',
   Claude37Sonnet = 'claude-3-7-sonnet-latest',