Add per-product AI verification disable option

Users can now disable AI verification for individual products that
AI is having trouble with (e.g., Amazon products where AI keeps
picking the main buy box price instead of "other sellers").

Changes:
- Add ai_verification_disabled column to products table
- Add toggle in product detail page under "Advanced Settings"
- Pass skip flag to scrapeProductWithVoting
- Skip AI verification when flag is set

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

backend/src/services/scheduler.ts

@@ -29,14 +29,18 @@ async function checkPrices(): Promise<void> {
         // Get anchor price for variant products (the price the user confirmed)
         const anchorPrice = await productQueries.getAnchorPrice(product.id);
 
-        console.log(`[Scheduler] Product ${product.id} - preferredMethod: ${preferredMethod}, anchorPrice: ${anchorPrice}`);
+        // Check if AI verification is disabled for this product
+        const skipAiVerification = await productQueries.isAiVerificationDisabled(product.id);
+
+        console.log(`[Scheduler] Product ${product.id} - preferredMethod: ${preferredMethod}, anchorPrice: ${anchorPrice}, skipAi: ${skipAiVerification}`);
 
         // Use voting scraper with preferred method and anchor price if available
         const scrapedData = await scrapeProductWithVoting(
           product.url,
           product.user_id,
           preferredMethod as ExtractionMethod | undefined,
-          anchorPrice || undefined
+          anchorPrice || undefined,
+          skipAiVerification
         );
 
         console.log(`[Scheduler] Product ${product.id} - scraped price: ${scrapedData.price?.price}, candidates: ${scrapedData.priceCandidates.map(c => `${c.price}(${c.method})`).join(', ')}`);