Add ASN info lookup and periodic routing table statistics

- Add handle and description columns to asns table
- Look up ASN info using asinfo package when creating new ASNs
- Remove noisy debug logging for individual route updates
- Add IPv4/IPv6 route counters and update rate tracking
- Log routing table statistics every 15 seconds with IPv4/IPv6 breakdown
- Track updates per second for both IPv4 and IPv6 routes separately

internal/database/schema.sql

@@ -1,6 +1,8 @@
 CREATE TABLE IF NOT EXISTS asns (
 	id TEXT PRIMARY KEY,
 	number INTEGER UNIQUE NOT NULL,
+	handle TEXT,
+	description TEXT,
 	first_seen DATETIME NOT NULL,
 	last_seen DATETIME NOT NULL
 );