fix(proxy): Use rotating IPs instead of sticky sessions

Removes session parameter from Evomi proxy URL so each request
gets a different IP. Prevents all workers from sharing same IP.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

backend/src/services/crawl-rotator.ts

@@ -1035,7 +1035,7 @@ export function getEvomiConfig(): EvomiConfig {
  * Build a geo-targeted Evomi proxy URL
  *
  * @param stateCode - US state code (e.g., 'AZ')
- * @param workerId - Worker ID for session stickiness
+ * @param workerId - Worker ID (ignored - using rotating IPs)
  * @param city - Optional city name (lowercase, dots for spaces)
  * @returns Proxy URL or null if Evomi not configured
  */
@@ -1056,14 +1056,6 @@ export function buildEvomiProxyUrl(
     return null;
   }
 
-  // Use the passed session ID directly (from identity pool) or generate from worker ID
-  // Identity pool passes unique session IDs like "scrapc-1702...-abc123"
-  // Regular callers pass worker IDs - we add region suffix for stickiness
-  const isIdentitySession = sessionOrWorkerId.includes('-') && sessionOrWorkerId.length > 20;
-  const sessionId = isIdentitySession
-    ? sessionOrWorkerId.replace(/[^a-zA-Z0-9]/g, '').slice(0, 20)  // Use identity session (max 20 chars)
-    : `${sessionOrWorkerId.replace(/[^a-zA-Z0-9]/g, '').slice(0, 6)}${region.slice(0, 4)}`;  // Worker ID + region
-
   // Build geo target string
   let geoParams = `_country-US_region-${region}`;
   let geoDisplay = region;
@@ -1073,9 +1065,8 @@ export function buildEvomiProxyUrl(
     geoDisplay = `${city}, ${region}`;
   }
 
-  // Build full proxy URL
+  // Build full proxy URL - rotating (no session = new IP each request)
-  // Format: http://user:pass_geo_session@host:port
+  const url = `http://${config.user}:${config.pass}${geoParams}@${config.host}:${config.port}`;
-  const url = `http://${config.user}:${config.pass}${geoParams}_session-${sessionId}_lifetime-${config.sessionLifetimeMinutes}@${config.host}:${config.port}`;
 
   return {
     url,