Show figures of the routing table on the home page (closes #154)

The home page gets cards for the newest and oldest kept route, the newest
and oldest updated AS, the AS with the most prefixes, the ASes with a
single prefix and fifteen well-known networks. Two more cards count the
bogon announcements and the prefixes with several origin ASes. They link
to the new pages /bogons and /multiple-origins, which list up to 1,000
entries each.

The new package internal/bogon tells reserved prefixes and AS numbers,
from the IANA special-purpose and address space registries. Table.Overview
walks the table and lets the read lock go every 10,000 prefixes. The
server works the cards out once a minute and serves that copy. A new index
on asns(last_seen) finds the newest and oldest updated AS.

Model: opus-5-5

internal/routewatch/app_integration_internal_test.go

@@ -223,6 +223,35 @@ func (m *mockStore) GetAS(_ context.Context, asn int) (*database.ASN, bool, erro
 	return &database.ASN{ASN: asn}, false, nil
 }
 
+// GetLastSeenASes returns copies of the stored ASes last seen most recently
+// and longest ago, or neither when none is stored.
+func (m *mockStore) GetLastSeenASes(
+	_ context.Context,
+) (*database.ASN, *database.ASN, error) {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+
+	var newest, oldest *database.ASN
+
+	for _, asn := range m.ASNs {
+		if newest == nil || asn.LastSeen.After(newest.LastSeen) {
+			newest = asn
+		}
+
+		if oldest == nil || asn.LastSeen.Before(oldest.LastSeen) {
+			oldest = asn
+		}
+	}
+
+	if newest == nil {
+		return nil, nil, nil
+	}
+
+	newestCopy, oldestCopy := *newest, *oldest
+
+	return &newestCopy, &oldestCopy, nil
+}
+
 // GetASWHOIS returns the stored AS, or only its number when none is stored.
 func (m *mockStore) GetASWHOIS(ctx context.Context, asn int) (*database.ASN, error) {
 	asnInfo, _, err := m.GetAS(ctx, asn)
@@ -605,12 +634,15 @@ func TestShutdownReturnsByItsDeadlineWhileAWriteIsBlocked(t *testing.T) {
 	cfg := &config.Config{Port: port}
 	s := streamer.New(log, metrics.New())
 
+	// A started server reads its routing table in the background, so it
+	// needs one.
 	rw := New(Dependencies{
 		DB:       store,
 		Streamer: s,
-		Server:   server.New(store, nil, s, log, cfg),
-		Logger:   log,
-		Config:   cfg,
+		Server: server.New(store, routetable.New(routetable.Params{}), s, log,
+			cfg),
+		Logger: log,
+		Config: cfg,
 	})
 
 	err := rw.server.Start(t.Context())