feat: env check auto-disables dummy_radio0 STA (2.4GHz recon root cause)

The stock STA client interface (wlan0) holds phy0's channel, pinning wlan0mon
so 2.4GHz recon captures nothing (verified: iw set channel -> Resource busy
until wlan0 is down). env_check now disables it (uci wireless.dummy_radio0
disabled=1 + wifi reload) at startup and /api/recon/status exposes wlan0_sta
so the recon page can warn if it regresses.

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

@@ -1359,6 +1359,7 @@ def h_recon_status(ctx):
                  'scanning': scanning, 'scan_remaining': remaining, 'stale': stale,
                  'hopper_online': _hopper_online(),
                  'wlan0_pinned': _wlan0_pinned(),
+                 'wlan0_sta': _sta_uplink_enabled(),
                  'wlan0_hopping': _wlan0_hopping(),
                  'history_reset': _recon_history_reset()}
 
@@ -3717,6 +3718,20 @@ def _wlan0_pinned():
     return False
 
 
+def _sta_uplink_enabled():
+    """True when the stock dummy_radio0 STA client interface is enabled. The
+    STA holds phy0's channel, which pins wlan0mon and starves 2.4GHz recon
+    entirely (iw set channel fails with Resource busy while it is up)."""
+    cfg = _uci_values('wireless.dummy_radio0') or {}
+    return cfg.get('mode') == 'sta' and cfg.get('disabled') != '1'
+
+
+def _disable_sta_uplink():
+    device_run(['uci', 'set', 'wireless.dummy_radio0.disabled=1'])
+    device_run(['uci', 'commit', 'wireless'])
+    device_run(['wifi', 'reload'], timeout=30)
+
+
 def _pineap_interfaces():
     """Runtime pineapd interface table from ``_pineap INTERFACE LIST``:
     {name: {'channels': int, 'bands': str, 'hop': str, 'pkts': int}}."""
@@ -3790,6 +3805,13 @@ def env_check():
     else:
         _env_step(report, 'warn', pool_detail)
 
+    if _sta_uplink_enabled():
+        _disable_sta_uplink()
+        _env_step(report, 'fixed', '2.4GHz recon: dummy_radio0 STA uplink disabled '
+                                  '(it was pinning phy0 so wlan0mon could not hop)')
+    else:
+        _env_step(report, 'pass', 'no STA uplink pinning phy0')
+
     raised = _raise_monitors()
     if raised:
         _env_step(report, 'fixed', 'monitor interfaces brought up', ', '.join(raised))

payload/user/remote_access/pager-webui/www/js/views.js

@@ -1462,7 +1462,7 @@ views.recon = (root) => {
                   compare: [], history: {}, mapBand: null,
                   archive: null, archives: [], scanRemaining: null,
                   hopperOnline: null, historyReset: false, scanErr: null,
-                  wlan0Pinned: false, wlan0Hopping: null };
+                  wlan0Pinned: false, wlan0Sta: false, wlan0Hopping: null };
   const cols = reconLoadCols();
 
   // ---- title cards (stat cards with optional mini charts) ----
@@ -1661,10 +1661,11 @@ views.recon = (root) => {
     if (state.hopperOnline === false) bits.push('Hopper radio offline — fewer networks seen');
     if (state.historyReset) bits.push('History reset — previous scans archived (see Previous Scans)');
     if (state.wlan0Pinned) bits.push('2.4GHz under-sampled — OpenAP/Evil WPA holds wlan0mon');
+    if (state.wlan0Sta) bits.push('2.4GHz starved — client STA (wlan0) pins phy0');
     if (state.wlan0Hopping === false) bits.push('2.4GHz starved — wlan0mon hopping is off');
     if (state.scanErr) bits.push(state.scanErr);
     scanStatus.textContent = bits.join(' · ');
-    scanStatus.classList.toggle('warn', state.hopperOnline === false || state.historyReset || state.wlan0Pinned || state.wlan0Hopping === false || !!state.scanErr);
+    scanStatus.classList.toggle('warn', state.hopperOnline === false || state.historyReset || state.wlan0Pinned || state.wlan0Sta || state.wlan0Hopping === false || !!state.scanErr);
   }
   scanToggle.addEventListener('change', () => {
     if (pendingScan) { scanToggle.checked = !scanToggle.checked; return; }
@@ -2527,6 +2528,7 @@ views.recon = (root) => {
       state.hopperOnline = r.data.hopper_online;
       state.historyReset = !!r.data.history_reset;
       state.wlan0Pinned = !!r.data.wlan0_pinned;
+      state.wlan0Sta = !!r.data.wlan0_sta;
       state.wlan0Hopping = r.data.wlan0_hopping;
       if (!pendingScan) scanToggle.checked = scanning;
       renderScanBar();

tests/test_env_check.py

@@ -217,6 +217,35 @@ class EnvCheckTest(unittest.TestCase):
         report = server.env_check()
         self.assertEqual(self.steps(report, 'wlan0mon hopping on')[0]['ok'], 'pass')
 
+    def test_sta_uplink_disabled_when_enabled(self):
+        self.safe_set()
+        self.uci_state['wireless.dummy_radio0.mode'] = 'sta'
+        self.uci_state['wireless.dummy_radio0.ifname'] = 'wlan0'
+        self.uci_state['wireless.dummy_radio0.disabled'] = '0'
+        report = server.env_check()
+        self.assertEqual(self.steps(report, 'dummy_radio0 STA uplink disabled')[0]['ok'], 'fixed')
+        self.assertEqual(self.uci_state['wireless.dummy_radio0.disabled'], '1')
+        self.assertIn(['wifi', 'reload'], self.runs)
+
+    def test_sta_uplink_pass_when_absent(self):
+        self.safe_set()
+        report = server.env_check()
+        self.assertEqual(self.steps(report, 'no STA uplink pinning phy0')[0]['ok'], 'pass')
+
+    def test_sta_uplink_pass_when_disabled(self):
+        self.safe_set()
+        self.uci_state['wireless.dummy_radio0.mode'] = 'sta'
+        self.uci_state['wireless.dummy_radio0.disabled'] = '1'
+        report = server.env_check()
+        self.assertEqual(self.steps(report, 'no STA uplink pinning phy0')[0]['ok'], 'pass')
+
+    def test_recon_status_exposes_sta(self):
+        self.safe_set()
+        self.uci_state['wireless.dummy_radio0.mode'] = 'sta'
+        status, payload = server.h_recon_status(type('C', (), {'query': {}})())
+        self.assertEqual(status, 200)
+        self.assertTrue(payload['wlan0_sta'])
+
     def test_cli_exits_zero_on_pass(self):
         self.safe_set()
         buf = io.StringIO()