fix: read real client IP from X-Forwarded-For behind Caddy/Docker

dashboard/backend/main.py

@@ -116,20 +116,20 @@ async def health():
 
 @app.get("/api/client-ip")
 async def client_ip(request: Request):
-    ip = request.client.host
-    if ip.startswith("192.168.31."):
-        return {"ip": ip, "lan": True}
-    if ip.startswith("100."):
-        import socket
-        try:
-            s = socket.socket()
-            s.settimeout(1)
-            s.connect(("192.168.31.1", 80))
-            s.close()
-            return {"ip": ip, "lan": True}
-        except Exception:
-            pass
-    return {"ip": ip, "lan": False}
+    ip = request.headers.get("x-forwarded-for", "").split(",")[0].strip() or request.client.host
+    lan = ip.startswith("192.168.31.") or (ip.startswith("100.") and _router_reachable())
+    return {"ip": ip, "lan": lan}
+
+def _router_reachable():
+    import socket
+    try:
+        s = socket.socket()
+        s.settimeout(1)
+        s.connect(("192.168.31.1", 80))
+        s.close()
+        return True
+    except Exception:
+        return False
 
 # Public auth endpoints
 app.include_router(auth.router, prefix="/api/auth", tags=["auth"])