feat(images): Add local image storage with on-demand resizing

- Store product images locally with hierarchy: /images/products/<state>/<store>/<brand>/<product>/
- Add /img/* proxy endpoint for on-demand resizing via Sharp
- Implement per-product image checking to skip existing downloads
- Fix pathToUrl() to correctly generate /images/... URLs
- Add frontend getImageUrl() helper with preset sizes (thumb, medium, large)
- Update all product pages to use optimized image URLs
- Add stealth session support for Dutchie GraphQL crawls
- Include test scripts for crawl and image verification

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

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

backend/src/platforms/dutchie/client.ts

@@ -213,7 +213,24 @@ const FINGERPRINTS: Fingerprint[] = [
 
 let currentFingerprintIndex = 0;
 
+// Forward declaration for session (actual CrawlSession interface defined later)
+let currentSession: {
+  sessionId: string;
+  fingerprint: Fingerprint;
+  proxyUrl: string | null;
+  stateCode?: string;
+  timezone?: string;
+  startedAt: Date;
+} | null = null;
+
+/**
+ * Get current fingerprint - returns session fingerprint if active, otherwise default
+ */
 export function getFingerprint(): Fingerprint {
+  // Use session fingerprint if a session is active
+  if (currentSession) {
+    return currentSession.fingerprint;
+  }
   return FINGERPRINTS[currentFingerprintIndex];
 }
 
@@ -228,6 +245,103 @@ export function resetFingerprint(): void {
   currentFingerprintIndex = 0;
 }
 
+/**
+ * Get a random fingerprint from the pool
+ */
+export function getRandomFingerprint(): Fingerprint {
+  const index = Math.floor(Math.random() * FINGERPRINTS.length);
+  return FINGERPRINTS[index];
+}
+
+// ============================================================
+// SESSION MANAGEMENT
+// Per-session fingerprint rotation for stealth
+// ============================================================
+
+export interface CrawlSession {
+  sessionId: string;
+  fingerprint: Fingerprint;
+  proxyUrl: string | null;
+  stateCode?: string;
+  timezone?: string;
+  startedAt: Date;
+}
+
+// Note: currentSession variable declared earlier in file for proper scoping
+
+/**
+ * Timezone to Accept-Language mapping
+ * US timezones all use en-US but this can be extended for international
+ */
+const TIMEZONE_TO_LOCALE: Record<string, string> = {
+  'America/Phoenix': 'en-US,en;q=0.9',
+  'America/Los_Angeles': 'en-US,en;q=0.9',
+  'America/Denver': 'en-US,en;q=0.9',
+  'America/Chicago': 'en-US,en;q=0.9',
+  'America/New_York': 'en-US,en;q=0.9',
+  'America/Detroit': 'en-US,en;q=0.9',
+  'America/Anchorage': 'en-US,en;q=0.9',
+  'Pacific/Honolulu': 'en-US,en;q=0.9',
+};
+
+/**
+ * Get Accept-Language header for a given timezone
+ */
+export function getLocaleForTimezone(timezone?: string): string {
+  if (!timezone) return 'en-US,en;q=0.9';
+  return TIMEZONE_TO_LOCALE[timezone] || 'en-US,en;q=0.9';
+}
+
+/**
+ * Start a new crawl session with a random fingerprint
+ * Call this before crawling a store to get a fresh identity
+ */
+export function startSession(stateCode?: string, timezone?: string): CrawlSession {
+  const baseFp = getRandomFingerprint();
+
+  // Override Accept-Language based on timezone for geographic consistency
+  const fingerprint: Fingerprint = {
+    ...baseFp,
+    acceptLanguage: getLocaleForTimezone(timezone),
+  };
+
+  currentSession = {
+    sessionId: `session_${Date.now()}_${Math.random().toString(36).slice(2, 8)}`,
+    fingerprint,
+    proxyUrl: currentProxy,
+    stateCode,
+    timezone,
+    startedAt: new Date(),
+  };
+
+  console.log(`[Dutchie Client] Started session ${currentSession.sessionId}`);
+  console.log(`[Dutchie Client]   Fingerprint: ${fingerprint.userAgent.slice(0, 50)}...`);
+  console.log(`[Dutchie Client]   Accept-Language: ${fingerprint.acceptLanguage}`);
+  if (timezone) {
+    console.log(`[Dutchie Client]   Timezone: ${timezone}`);
+  }
+
+  return currentSession;
+}
+
+/**
+ * End the current crawl session
+ */
+export function endSession(): void {
+  if (currentSession) {
+    const duration = Math.round((Date.now() - currentSession.startedAt.getTime()) / 1000);
+    console.log(`[Dutchie Client] Ended session ${currentSession.sessionId} (${duration}s)`);
+    currentSession = null;
+  }
+}
+
+/**
+ * Get current active session
+ */
+export function getCurrentSession(): CrawlSession | null {
+  return currentSession;
+}
+
 // ============================================================
 // CURL HTTP CLIENT
 // ============================================================