feat(sync): add GoMag API client with Phase 0 auto-download

- New gomag_client.py service: async httpx client that downloads orders
  from GoMag API with full pagination and 1s rate-limit sleep
- config.py: add GOMAG_API_KEY, GOMAG_API_SHOP, GOMAG_ORDER_DAYS_BACK,
  GOMAG_LIMIT, GOMAG_API_URL settings
- sync_service.py: Phase 0 downloads fresh orders before reading JSONs;
  graceful skip if API keys not configured
- start.sh: auto-detect INSTANTCLIENTPATH from .env, fallback to thin mode
- .env.example: document GoMag API variables

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

start.sh

@@ -28,7 +28,27 @@ fi
 
 # Oracle config
 export TNS_ADMIN="$(pwd)/api"
-export LD_LIBRARY_PATH=/opt/oracle/instantclient_21_15:$LD_LIBRARY_PATH
+
+# Detect Oracle Instant Client path from .env or use default
+INSTANTCLIENT_PATH=""
+if [ -f "api/.env" ]; then
+    INSTANTCLIENT_PATH=$(grep -E "^INSTANTCLIENTPATH=" api/.env | cut -d'=' -f2- | tr -d ' ')
+fi
+# Fallback to default path if not set in .env
+if [ -z "$INSTANTCLIENT_PATH" ]; then
+    INSTANTCLIENT_PATH="/opt/oracle/instantclient_21_15"
+fi
+
+if [ -d "$INSTANTCLIENT_PATH" ]; then
+    echo "Oracle Instant Client found: $INSTANTCLIENT_PATH (thick mode)"
+    export LD_LIBRARY_PATH="$INSTANTCLIENT_PATH:$LD_LIBRARY_PATH"
+else
+    echo "WARN: Oracle Instant Client NOT found la: $INSTANTCLIENT_PATH"
+    echo "      Se va folosi thin mode (Oracle 12.1+ necesar)."
+    echo "      Pentru thick mode: instaleaza instantclient sau seteaza INSTANTCLIENTPATH in api/.env"
+    # Force thin mode so app doesn't try to load missing libraries
+    export FORCE_THIN_MODE=true
+fi
 
 cd api
 echo "Starting GoMag Import Manager on http://0.0.0.0:5003"