feat(api): enhance peer session management and documentation

- Added new fields to the API for tracking connected speakers and session states across multiple nodes, including `connected_speaker_id`, `connected_speaker_label`, `session_on_speakers`, `established_on_speakers`, and `session_mismatch`.
- Implemented a new endpoint for retrieving bird protocol sessions, enhancing the agent server functionality.
- Updated the OpenAPI documentation to reflect the new fields and query parameters, improving clarity for API consumers.
- Modified the frontend to display connected speaker information and session states, providing better visibility into peer connections.
- Updated deployment documentation to clarify the configuration requirements for enabling IP forwarding on VPS.

internal/httpapi/peers_live_test.go

@@ -0,0 +1,67 @@
+package httpapi
+
+import (
+	"testing"
+
+	"evobgp/internal/birdfmt"
+	"evobgp/internal/store"
+)
+
+func TestMatchPeerOnSpeakers_establishedOnReplica(t *testing.T) {
+	peer := &store.BGPPeer{
+		ID:       "aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee",
+		Neighbor: "198.51.100.2",
+	}
+	views := []speakerBGPLive{
+		{
+			SpeakerID: "master-id",
+			Label:     "CP · bgp.shz.su",
+			Sessions: []birdfmt.BGPSession{
+				{Name: birdfmt.PeerProtocolName(peer.ID), Neighbor: "198.51.100.2", State: "Idle"},
+			},
+		},
+		{
+			SpeakerID: "replica-id",
+			Label:     "bgp2.shz.su",
+			Sessions: []birdfmt.BGPSession{
+				{Name: birdfmt.PeerProtocolName(peer.ID), Neighbor: "198.51.100.2", State: "Established"},
+			},
+		},
+	}
+	state, connID, connLabel, established, on, mismatch := matchPeerOnSpeakers(peer, views)
+	if state != "Established" || connID != "replica-id" || connLabel != "bgp2.shz.su" {
+		t.Fatalf("got state=%q conn=%q label=%q", state, connID, connLabel)
+	}
+	if mismatch || len(on) != 2 || len(established) != 1 {
+		t.Fatalf("on=%+v established=%+v mismatch=%v", on, established, mismatch)
+	}
+}
+
+func TestMatchPeerOnSpeakers_multipleEstablished(t *testing.T) {
+	peer := &store.BGPPeer{ID: "aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee", Neighbor: "198.51.100.2"}
+	views := []speakerBGPLive{
+		{SpeakerID: "a", Label: "n1", Sessions: []birdfmt.BGPSession{{Name: birdfmt.PeerProtocolName(peer.ID), State: "Established"}}},
+		{SpeakerID: "b", Label: "n2", Sessions: []birdfmt.BGPSession{{Name: birdfmt.PeerProtocolName(peer.ID), State: "Established"}}},
+	}
+	_, connID, label, established, _, mismatch := matchPeerOnSpeakers(peer, views)
+	if mismatch || connID != "" || label != "n1, n2" || len(established) != 2 {
+		t.Fatalf("connID=%q label=%q established=%+v mismatch=%v", connID, label, established, mismatch)
+	}
+}
+
+func TestMatchPeerOnSpeakers_mismatchConfiguredSpeaker(t *testing.T) {
+	replica := "replica-id"
+	peer := &store.BGPPeer{
+		ID:        "aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee",
+		Neighbor:  "198.51.100.2",
+		SpeakerID: &replica,
+	}
+	views := []speakerBGPLive{
+		{SpeakerID: "master-id", Label: "CP", Sessions: []birdfmt.BGPSession{{Name: birdfmt.PeerProtocolName(peer.ID), State: "Established"}}},
+		{SpeakerID: replica, Label: "bgp2", Sessions: []birdfmt.BGPSession{{Name: birdfmt.PeerProtocolName(peer.ID), State: "Idle"}}},
+	}
+	_, _, _, _, _, mismatch := matchPeerOnSpeakers(peer, views)
+	if !mismatch {
+		t.Fatal("expected mismatch when configured replica has no Established")
+	}
+}