Add IP information API with background WHOIS fetcher

- Add /ip and /ip/{addr} JSON endpoints returning comprehensive IP info
- Include ASN, netblock, country code, org name, abuse contact, RIR data
- Extend ASN schema with WHOIS fields (country, org, abuse contact, etc)
- Create background WHOIS fetcher for rate-limited ASN info updates
- Store raw WHOIS responses for debugging and data preservation
- Queue on-demand WHOIS lookups when stale data is requested
- Refactor handleIPInfo to serve all IP endpoints consistently

internal/routewatch/app_integration_test.go

@@ -302,6 +302,39 @@ func (m *mockStore) GetASPeersContext(ctx context.Context, asn int) ([]database.
 	return m.GetASPeers(asn)
 }
 
+// GetIPInfo mock implementation
+func (m *mockStore) GetIPInfo(ip string) (*database.IPInfo, error) {
+	return m.GetIPInfoContext(context.Background(), ip)
+}
+
+// GetIPInfoContext mock implementation with context support
+func (m *mockStore) GetIPInfoContext(ctx context.Context, ip string) (*database.IPInfo, error) {
+	now := time.Now()
+	return &database.IPInfo{
+		IP:          ip,
+		Netblock:    "8.8.8.0/24",
+		MaskLength:  24,
+		IPVersion:   4,
+		NumPeers:    3,
+		ASN:         15169,
+		Handle:      "GOOGLE",
+		Description: "Google LLC",
+		CountryCode: "US",
+		FirstSeen:   now.Add(-24 * time.Hour),
+		LastSeen:    now,
+	}, nil
+}
+
+// GetNextStaleASN mock implementation
+func (m *mockStore) GetNextStaleASN(ctx context.Context, staleThreshold time.Duration) (int, error) {
+	return 0, database.ErrNoStaleASN
+}
+
+// UpdateASNWHOIS mock implementation
+func (m *mockStore) UpdateASNWHOIS(ctx context.Context, update *database.ASNWHOISUpdate) error {
+	return nil
+}
+
 // UpsertLiveRouteBatch mock implementation
 func (m *mockStore) UpsertLiveRouteBatch(routes []*database.LiveRoute) error {
 	m.mu.Lock()