feat: real-time WebSocket metrics broadcaster and UI updates

- New metrics_broadcaster service (410 lines) — background broadcaster
  pushing CPU/RAM/disk/network stats to subscribed WebSocket clients
- WebSocket protocol extended: subscribe/unsubscribe channels,
  get_rrd/get_node_rrd requests with request_id
- main.py: metrics broadcaster started in lifespan, WS message dispatcher
- websocket_manager.py: subscription map support
- templates: dashboard, instance_detail, proxmox_server_detail,
  proxmox_vms, workspaces — real-time charts and UI updates
- auth.py, servers.py, settings.py: minor fixes

backend/app/api/auth.py

@@ -216,6 +216,26 @@ def login(login_data: LoginRequest, request: Request, db: Session = Depends(get_
     }
 
 
+@router.post("/api/auth/refresh", response_model=Token)
+def refresh_token(
+    current_user: User = Depends(get_current_user),
+    session_token: str = Depends(get_current_session_token),
+    db: Session = Depends(get_db)
+):
+    """Refresh JWT access token without re-login (extends session)"""
+    session_timeout = SecurityService.get_setting_int(db, "session_timeout_minutes", 60)
+    access_token_expires = timedelta(minutes=session_timeout)
+    new_token = create_access_token(
+        data={"sub": current_user.username},
+        session_token=session_token,
+        expires_delta=access_token_expires
+    )
+    return {
+        "access_token": new_token,
+        "token_type": "bearer"
+    }
+
+
 @router.post("/api/auth/logout")
 def logout(
     request: Request, 

backend/app/api/proxmox/servers.py

@@ -33,9 +33,11 @@ def vms_page(request: Request, db: Session = Depends(get_db)):
     """Страница управления Proxmox серверами, VM и LXC"""
     from ...i18n import t
     lang = request.cookies.get("language", "en")
-    
+
+    # All servers are needed for cluster modals (admin operations).
+    # The main servers table is rendered dynamically via JS with workspace filtering.
     proxmox_servers = db.query(ProxmoxServer).all()
-    
+
     context = {
         "request": request,
         "proxmox_servers": proxmox_servers,

backend/app/api/settings.py

@@ -75,13 +75,11 @@ class ChangePasswordRequest(BaseModel):
 
 class PanelSettingsResponse(BaseModel):
     panel_name: str
-    refresh_interval: int  # seconds
     log_retention_days: int
     language: str  # ru or en
 
 
 class UpdatePanelSettingsRequest(BaseModel):
-    refresh_interval: Optional[int] = Field(None, ge=1, le=60)
     log_retention_days: Optional[int] = Field(None, ge=1, le=365)
     language: Optional[str] = Field(None, pattern='^(ru|en)$')
 
@@ -269,13 +267,11 @@ async def get_panel_settings(
     from ..config import settings
     
     # Get settings from database or use defaults
-    refresh_interval = get_setting(db, "refresh_interval", "5")
     log_retention_days = get_setting(db, "log_retention_days", "30")
     language = get_setting(db, "language", "ru")
     
     return {
         "panel_name": settings.PANEL_NAME,
-        "refresh_interval": int(refresh_interval),
         "log_retention_days": int(log_retention_days),
         "language": language
     }
@@ -291,10 +287,6 @@ async def update_panel_settings(
     updated_fields = []
     
     # Save settings to database
-    if data.refresh_interval is not None:
-        set_setting(db, "refresh_interval", str(data.refresh_interval), "Интервал обновления данных (секунды)")
-        updated_fields.append(f"refresh_interval={data.refresh_interval}")
-    
     if data.log_retention_days is not None:
         set_setting(db, "log_retention_days", str(data.log_retention_days), "Срок хранения логов (дни)")
         updated_fields.append(f"log_retention_days={data.log_retention_days}")