fix(reliability): probe section existence via uci show, not an option key

payload/user/remote_access/pager-webui/mk8_guard.py

@@ -34,9 +34,10 @@ def _pool_size():
 def _ensure_pineapd_section():
     """Stock daemon rewrites and profile restores can drop the whole
     `config pineapd` section; every @pineapd[0] option write fails with
-    'Invalid argument' until it exists again."""
-    rc, out, err = device_run(['uci', '-q', 'get',
-                               'pineapd.@pineapd[0].logrecon'])
+    'Invalid argument' until it exists again. Probes SECTION existence
+    (`uci -q show @pineapd[0]`) — never an option, which may legitimately
+    be absent from a rewritten section."""
+    rc, out, err = device_run(['uci', '-q', 'show', 'pineapd.@pineapd[0]'])
     if rc == 0:
         return False
     device_run(['uci', 'add', 'pineapd', 'pineapd'])