feat(01-01): install Go 1.24, initialize module, create shared types

- Initialize Go module github.com/netsynth/netsynth with Go 1.24.1
- Create classify/types.go with 11 TrafficClass constants (ICMP, DNS, HTTPS,
  HTTP, SSH, SMTP, NTP, DHCP, other-TCP, other-UDP, unknown)
- Add ClassifiedPacket and WindowSnapshot shared types
- Add Phase 1 dependencies: gopacket v1.5.0, go-pcap, cobra v1.10.2

go.mod

@@ -0,0 +1,14 @@
+module github.com/netsynth/netsynth
+
+go 1.24.1
+
+require (
+	github.com/gopacket/gopacket v1.5.0 // indirect
+	github.com/inconshreveable/mousetrap v1.1.0 // indirect
+	github.com/packetcap/go-pcap v0.0.0-20251215121130-f2cf9f991e7c // indirect
+	github.com/sirupsen/logrus v1.9.3 // indirect
+	github.com/spf13/cobra v1.10.2 // indirect
+	github.com/spf13/pflag v1.0.9 // indirect
+	golang.org/x/net v0.39.0 // indirect
+	golang.org/x/sys v0.32.0 // indirect
+)