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/prefixhandler.go

@@ -182,9 +182,15 @@ func (h *PrefixHandler) flushBatchLocked() {
 	var routesToUpsert []*database.LiveRoute
 	var routesToDelete []database.LiveRouteDeletion
 
-	// Skip the prefix table updates entirely - just update live_routes
-	// The prefix table is not critical for routing lookups
+	// Collect unique prefixes to update
+	prefixesToUpdate := make(map[string]time.Time)
+
 	for _, update := range prefixMap {
+		// Track prefix for both announcements and withdrawals
+		if _, exists := prefixesToUpdate[update.prefix]; !exists || update.timestamp.After(prefixesToUpdate[update.prefix]) {
+			prefixesToUpdate[update.prefix] = update.timestamp
+		}
+
 		if update.messageType == "announcement" && update.originASN > 0 {
 			// Create live route for batch upsert
 			route := h.createLiveRoute(update)
@@ -228,6 +234,13 @@ func (h *PrefixHandler) flushBatchLocked() {
 		}
 	}
 
+	// Update prefix tables
+	if len(prefixesToUpdate) > 0 {
+		if err := h.db.UpdatePrefixesBatch(prefixesToUpdate); err != nil {
+			h.logger.Error("Failed to update prefix batch", "error", err, "count", len(prefixesToUpdate))
+		}
+	}
+
 	elapsed := time.Since(startTime)
 	h.logger.Debug("Flushed prefix batch",
 		"batch_size", batchSize,