Switch from Sonnet 4 to Haiku 3.5 to reduce API costs

Sonnet 4 is ~4-12x more expensive than Haiku 3.5.
Haiku 3.5 should still be capable enough for price extraction.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: clucraft

backend/src/services/ai-extractor.ts

@@ -173,7 +173,7 @@ async function extractWithAnthropic(
   const preparedHtml = prepareHtmlForAI(html);
 
   const response = await anthropic.messages.create({
-    model: 'claude-sonnet-4-20250514',
+    model: 'claude-3-5-haiku-20241022',
     max_tokens: 1024,
     messages: [
       {
@@ -269,7 +269,7 @@ async function verifyWithAnthropic(
     .replace('$CURRENCY$', currency) + preparedHtml;
 
   const response = await anthropic.messages.create({
-    model: 'claude-sonnet-4-20250514',
+    model: 'claude-3-5-haiku-20241022',
     max_tokens: 512,
     messages: [{ role: 'user', content: prompt }],
   });
@@ -625,7 +625,7 @@ async function arbitrateWithAnthropic(
   const prompt = ARBITRATION_PROMPT.replace('$CANDIDATES$', candidatesList) + preparedHtml;
 
   const response = await anthropic.messages.create({
-    model: 'claude-sonnet-4-20250514',
+    model: 'claude-3-5-haiku-20241022',
     max_tokens: 512,
     messages: [{ role: 'user', content: prompt }],
   });