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.

docs/openapi.yaml

@@ -755,6 +755,42 @@ components:
         bgp_speaker_id:
           type: ["string", "null"]
           description: "`null` - политика для всех спикеров."
+        connected_speaker_id:
+          type: ["string", "null"]
+          description: >
+            Live (GET /v1/peers?live=1): спикер, на котором сессия Established; опрос CP birdc + agent /v1/agent/bird/protocols.
+        connected_speaker_label:
+          type: string
+          description: Человекочитаемая метка ноды из live-опроса.
+        session_on_speakers:
+          type: array
+          description: Состояние протокола пира на каждой опрошенной ноде.
+          items:
+            type: object
+            properties:
+              speaker_id:
+                type: string
+              label:
+                type: string
+              state:
+                type: string
+        established_on_speakers:
+          type: array
+          description: Ноды, где сессия в состоянии Established (один пир может быть на нескольких).
+          items:
+            type: object
+            properties:
+              speaker_id:
+                type: string
+              label:
+                type: string
+              state:
+                type: string
+        session_mismatch:
+          type: boolean
+          description: >
+            true если bgp_speaker_id задан, но на этой ноде нет Established
+            (сессия может быть на других нодах — это не ошибка для tenant-wide пиров).
         policies_json:
           type: string
           description: >
@@ -2156,6 +2192,13 @@ paths:
         - $ref: "#/components/parameters/Cursor"
         - $ref: "#/components/parameters/Limit"
         - $ref: "#/components/parameters/SpeakerFilter"
+        - name: live
+          in: query
+          schema:
+            type: string
+            enum: ["1"]
+          description: >
+            Опрос birdc на CP и GET /v1/agent/bird/protocols на репликах; обогащает session_state и connected_speaker_*.
       responses:
         "200":
           description: Успешно.