Major schema refactoring: simplify ASN and prefix tracking

- Remove UUID primary keys from ASNs table, use ASN number as primary key
- Update announcements table to reference ASN numbers directly
- Rename asns.number column to asns.asn for consistency
- Add prefix tracking to PrefixHandler to populate prefixes_v4/v6 tables
- Add UpdatePrefixesBatch method for efficient batch updates
- Update all database methods and models to use new schema
- Fix all references in code to use ASN field instead of Number
- Update test mocks to match new interfaces

internal/routewatch/app_integration_test.go

@@ -61,8 +61,7 @@ func (m *mockStore) GetOrCreateASN(number int, timestamp time.Time) (*database.A
 	}
 
 	asn := &database.ASN{
-		ID:        uuid.New(),
-		Number:    number,
+		ASN:       number,
 		FirstSeen: timestamp,
 		LastSeen:  timestamp,
 	}
@@ -72,6 +71,37 @@ func (m *mockStore) GetOrCreateASN(number int, timestamp time.Time) (*database.A
 	return asn, nil
 }
 
+// UpdatePrefixesBatch mock implementation
+func (m *mockStore) UpdatePrefixesBatch(prefixes map[string]time.Time) error {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+
+	for prefix, timestamp := range prefixes {
+		if p, exists := m.Prefixes[prefix]; exists {
+			p.LastSeen = timestamp
+		} else {
+			const (
+				ipVersionV4 = 4
+				ipVersionV6 = 6
+			)
+
+			ipVersion := ipVersionV4
+			if strings.Contains(prefix, ":") {
+				ipVersion = ipVersionV6
+			}
+
+			m.Prefixes[prefix] = &database.Prefix{
+				ID:        uuid.New(),
+				Prefix:    prefix,
+				IPVersion: ipVersion,
+				FirstSeen: timestamp,
+				LastSeen:  timestamp,
+			}
+		}
+	}
+	return nil
+}
+
 // GetOrCreatePrefix mock implementation
 func (m *mockStore) GetOrCreatePrefix(prefix string, timestamp time.Time) (*database.Prefix, error) {
 	m.mu.Lock()
@@ -302,8 +332,7 @@ func (m *mockStore) GetOrCreateASNBatch(asns map[int]time.Time) error {
 	for number, timestamp := range asns {
 		if _, exists := m.ASNs[number]; !exists {
 			m.ASNs[number] = &database.ASN{
-				ID:        uuid.New(),
-				Number:    number,
+				ASN:       number,
 				FirstSeen: timestamp,
 				LastSeen:  timestamp,
 			}