docs: add jsonl import usage to README

Author: Anshumancanrock

README.md

@@ -220,6 +220,29 @@ Print the Tor hostname:
   ./scripts/print_tor_hostname
   ```
 
+### Importing events from JSON Lines
+
+You can import NIP-01 events from a `.jsonl` file directly into the relay database.
+
+Basic import:
+  ```
+  npm run import -- ./events.jsonl
+  ```
+
+Set a custom batch size (default: `1000`):
+  ```
+  npm run import -- ./events.jsonl --batch-size 500
+  ```
+
+The importer:
+
+- Processes the file line-by-line to keep memory usage bounded.
+- Validates NIP-01 schema, event id hash, and Schnorr signature before insertion.
+- Inserts in database transactions per batch.
+- Skips duplicates without failing the whole import.
+- Prints progress in the format:
+  `[Processed: 50,000 | Inserted: 45,000 | Skipped: 5,000 | Errors: 0]`
+
 ### Running as a Service
 
 By default this server will run continuously until you stop it with Ctrl+C or until the system restarts.