feat: add server-side ETL pipeline, revert client to NocoDB reads

ETL Pipeline (server):
- POST /api/etl/sync?mode=full|incremental — fetches ERP, aggregates, writes NocoDB
- nocodbClient.ts: table discovery, paginated delete/insert
- etlSync.ts: orchestrates fetch → aggregate → upsert
- museumMapping.ts moved from client to server
- Auth via ETL_SECRET bearer token

Client:
- dataService.ts reverts to reading NocoDB DailySales table
- Paginated fetch via fetchNocoDBTable (handles >1000 rows)
- Suspicious data check: prefers cache if NocoDB returns <10 rows
- Deleted erpService.ts and client-side museumMapping.ts

First full sync: 391K transactions → 5,760 daily records in 108s.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/config/museumMapping.ts

@@ -1,38 +0,0 @@
-// Definitive mapping of ERP product descriptions to museum names.
-// Priority order matters — first match wins (handles combo tickets).
-
-const MUSEUM_KEYWORDS: [string, string[]][] = [
-  ['Revelation Exhibition', ['Revelation', 'الوحي']],
-  ['Creation Story Museum', ['Creation Story', 'قصة الخلق']],
-  ['Holy Quraan Museum', ['Holy Quraan', 'القرآن الكريم']],
-  ['Trail To Hira Cave', ['Trail To Hira', 'غار حراء']],
-  ['Makkah Greets Us', ['Makkah Greets']],
-  ['VIP Experience', ['VIP Experience']],
-];
-
-export const MUSEUM_NAMES = MUSEUM_KEYWORDS.map(([name]) => name);
-
-export function getMuseumFromProduct(productDescription: string): string {
-  const desc = productDescription.trim();
-  for (const [museum, keywords] of MUSEUM_KEYWORDS) {
-    for (const kw of keywords) {
-      if (desc.includes(kw)) return museum;
-    }
-  }
-  return 'Other';
-}
-
-export const CHANNEL_LABELS: Record<string, string> = {
-  'B2C': 'HiHala Website/App',
-  'B2B': 'B2B',
-  'POS': 'POS',
-  'Safiyyah POS': 'Safiyyah POS',
-  'Standalone': 'Standalone',
-  'Mobile': 'Mobile',
-  'Viva': 'Viva',
-  'IT': 'IT',
-};
-
-export function getChannelLabel(operatingAreaName: string): string {
-  return CHANNEL_LABELS[operatingAreaName] || operatingAreaName;
-}