feat: migrate museum sales from NocoDB to Hono ERP API

- Replace NocoDB museum data (Districts/Museums/DailyStats) with ERP API
- Client fetches via server proxy (/api/erp/sales) — no credentials in browser
- Aggregate transaction-level ERP data into daily/museum/channel records
- Replace "district" dimension with "channel" (B2C/HiHala, POS, B2B, etc.)
- Add product-to-museum mapping (46 products → 6 museums)
- NocoDB retained only for PilgrimStats
- Remove old server/index.js (replaced by modular TS in server/src/)
- Update all components, types, and locale files

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

.env.example

@@ -1,8 +1,4 @@
-# NocoDB (primary data source)
+# NocoDB (PilgrimStats only — museum sales come from ERP API via server proxy)
 VITE_NOCODB_URL=http://localhost:8090
-VITE_NOCODB_TOKEN=your_token_here
-VITE_NOCODB_BASE_ID=your_base_id_here
-
-# Google Sheets (fallback if NocoDB fails)
-VITE_SHEETS_ID=your_spreadsheet_id_here
-VITE_SHEETS_NAME=Consolidated Data
+VITE_NOCODB_TOKEN=your-token
+VITE_NOCODB_BASE_ID=your-base-id