fix: sync AgentLive.Index modal state to URL for browser navigation

Update AgentLive.Index to properly handle browser back/forward buttons
by syncing the setup token modal to URL parameters.

Changes:
- Update handle_params/3 to read modal param and set modal state
- Update show_setup handler to use push_patch with ?modal=setup
- Update close_token_modal handler to use push_patch (remove modal param)
- Update handle_agent_creation_success to use push_patch after creating agent

Behavior:
- Browser back button now closes the setup modal without navigating away
- URL reflects current modal state (?modal=setup)
- Bookmarkable URLs restore exact modal state (can share agent setup URL)
- After creating agent, modal opens via URL state

Follows idiomatic Phoenix LiveView pattern using push_patch/2 and
handle_params/3 as documented in CLAUDE.md.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

lib/towerops_web/live/agent_live/index.ex

@@ -77,7 +77,15 @@ defmodule ToweropsWeb.AgentLive.Index do
 
   @impl true
   def handle_params(params, _url, socket) do
-    {:noreply, apply_action(socket, socket.assigns.live_action, params)}
+    # Read modal state from URL
+    modal = params["modal"]
+
+    socket =
+      socket
+      |> assign(:show_token_modal, modal == "setup")
+      |> apply_action(socket.assigns.live_action, params)
+
+    {:noreply, socket}
   end
 
   @impl true
@@ -105,8 +113,8 @@ defmodule ToweropsWeb.AgentLive.Index do
   def handle_event("close_token_modal", _params, socket) do
     {:noreply,
      socket
-     |> assign(:show_token_modal, false)
-     |> assign(:new_token, nil)}
+     |> assign(:new_token, nil)
+     |> push_patch(to: ~p"/agents")}
   end
 
   @impl true
@@ -116,7 +124,7 @@ defmodule ToweropsWeb.AgentLive.Index do
     {:noreply,
      socket
      |> assign(:new_token, %{agent_token: agent_token, token: agent_token.token})
-     |> assign(:show_token_modal, true)}
+     |> push_patch(to: ~p"/agents?modal=setup")}
   end
 
   @impl true
@@ -308,9 +316,9 @@ defmodule ToweropsWeb.AgentLive.Index do
      |> assign(:assignment_breakdown, assignment_breakdown)
      |> assign(:offline_agents, offline_agents)
      |> assign(:new_token, %{agent_token: agent_token, token: token})
-     |> assign(:show_token_modal, true)
      |> assign(:agent_form, to_form(%{"name" => "", "is_cloud_poller" => false}))
-     |> put_flash(:info, success_message)}
+     |> put_flash(:info, success_message)
+     |> push_patch(to: ~p"/agents?modal=setup")}
   end
 
   defp load_cloud_pollers_if_superuser(scope) do

test/towerops/snmp/profiles/vendors/cambium_test.exs

@@ -85,13 +85,22 @@ defmodule Towerops.Snmp.Profiles.Vendors.CambiumTest do
     end
   end
 
-  describe "discover_wireless_sensors/1" do
-    test "discovers sensors when SNMP responds" do
+  describe "discover_wireless_sensors/1 - static sensors" do
+    test "discovers static sensors when SNMP responds" do
       defs = Cambium.wireless_oid_defs()
       num_defs = length(defs)
 
-      expect(SnmpMock, :get, num_defs, fn _, _oid, _ ->
-        {:ok, 42}
+      # Expect mode check + static sensor calls
+      stub(SnmpMock, :get, fn _, oid, _ ->
+        case oid do
+          # Mode check fails (not ePMP)
+          "1.3.6.1.4.1.17713.21.1.2.32.0" ->
+            {:error, :no_such_object}
+
+          # Static CPU sensor
+          _ ->
+            {:ok, 42}
+        end
       end)
 
       sensors = Cambium.discover_wireless_sensors(@client_opts)
@@ -99,13 +108,218 @@ defmodule Towerops.Snmp.Profiles.Vendors.CambiumTest do
       assert is_list(sensors)
       assert length(sensors) == num_defs
     end
+  end
 
-    test "returns empty list when no sensors respond" do
-      defs = Cambium.wireless_oid_defs()
-      num_defs = length(defs)
+  describe "discover_wireless_sensors/1 - ePMP Access Point" do
+    test "discovers all wireless sensors for ePMP AP mode" do
+      # Mock ePMP detection and sensor values
+      expect(SnmpMock, :get, fn _, oid, _ ->
+        cond do
+          # wirelessInterfaceMode (1 = AP mode)
+          oid == "1.3.6.1.4.1.17713.21.1.2.32.0" ->
+            {:ok, 1}
 
-      expect(SnmpMock, :get, num_defs, fn _, _, _ ->
-        {:error, :no_such_object}
+          # RSSI
+          oid == "1.3.6.1.4.1.17713.21.1.2.3.0" ->
+            {:ok, -65}
+
+          # SNR
+          oid == "1.3.6.1.4.1.17713.21.1.2.18.0" ->
+            {:ok, 25}
+
+          # Frequency
+          oid == "1.3.6.1.4.1.17713.21.1.2.1.0" ->
+            {:ok, 5180}
+
+          # Client count (AP mode only)
+          oid == "1.3.6.1.4.1.17713.21.1.2.10.0" ->
+            {:ok, 12}
+
+          # Static CPU sensor
+          oid == "1.3.6.1.2.1.25.3.3.1.2.1" ->
+            {:ok, 45}
+
+          true ->
+            {:error, :no_such_object}
+        end
+      end)
+
+      sensors = Cambium.discover_wireless_sensors(@client_opts)
+
+      # Should have: 1 static + 4 ePMP sensors (RSSI, SNR, Freq, Clients)
+      assert length(sensors) == 5
+
+      # Check RSSI sensor
+      rssi_sensor = Enum.find(sensors, &(&1.sensor_type == "rssi"))
+      assert rssi_sensor
+      assert rssi_sensor.sensor_descr == "Downlink RSSI"
+      assert rssi_sensor.last_value == -65
+      assert rssi_sensor.sensor_unit == "dBm"
+
+      # Check SNR sensor
+      snr_sensor = Enum.find(sensors, &(&1.sensor_type == "snr"))
+      assert snr_sensor
+      assert snr_sensor.sensor_descr == "Downlink SNR"
+      assert snr_sensor.last_value == 25
+      assert snr_sensor.sensor_unit == "dB"
+
+      # Check Frequency sensor
+      freq_sensor = Enum.find(sensors, &(&1.sensor_type == "frequency"))
+      assert freq_sensor
+      assert freq_sensor.sensor_descr == "RF Frequency"
+      assert freq_sensor.last_value == 5180
+      assert freq_sensor.sensor_unit == "MHz"
+
+      # Check Clients sensor (AP mode only)
+      clients_sensor = Enum.find(sensors, &(&1.sensor_type == "clients"))
+      assert clients_sensor
+      assert clients_sensor.sensor_descr == "Connected Subscribers"
+      assert clients_sensor.last_value == 12
+    end
+  end
+
+  describe "discover_wireless_sensors/1 - ePMP Subscriber Module" do
+    test "discovers wireless sensors for ePMP SM mode (no client count)" do
+      # Mock wirelessInterfaceMode (2 = SM mode)
+      expect(SnmpMock, :get, fn _, oid, _ ->
+        cond do
+          oid == "1.3.6.1.4.1.17713.21.1.2.32.0" ->
+            {:ok, 2}
+
+          # RSSI
+          oid == "1.3.6.1.4.1.17713.21.1.2.3.0" ->
+            {:ok, -72}
+
+          # SNR
+          oid == "1.3.6.1.4.1.17713.21.1.2.18.0" ->
+            {:ok, 18}
+
+          # Frequency
+          oid == "1.3.6.1.4.1.17713.21.1.2.1.0" ->
+            {:ok, 5220}
+
+          # Static CPU sensor
+          oid == "1.3.6.1.2.1.25.3.3.1.2.1" ->
+            {:ok, 35}
+
+          true ->
+            {:error, :no_such_object}
+        end
+      end)
+
+      sensors = Cambium.discover_wireless_sensors(@client_opts)
+
+      # Should have: 1 static + 3 ePMP sensors (RSSI, SNR, Freq) - NO clients
+      assert length(sensors) == 4
+
+      # Verify no clients sensor in SM mode
+      refute Enum.any?(sensors, &(&1.sensor_type == "clients"))
+
+      # But should have RSSI, SNR, Frequency
+      assert Enum.any?(sensors, &(&1.sensor_type == "rssi"))
+      assert Enum.any?(sensors, &(&1.sensor_type == "snr"))
+      assert Enum.any?(sensors, &(&1.sensor_type == "frequency"))
+    end
+  end
+
+  describe "discover_wireless_sensors/1 - non-ePMP device" do
+    test "returns only static sensors when device is not ePMP" do
+      # Mock wirelessInterfaceMode check fails (not ePMP)
+      expect(SnmpMock, :get, fn _, oid, _ ->
+        case oid do
+          "1.3.6.1.4.1.17713.21.1.2.32.0" ->
+            {:error, :no_such_object}
+
+          "1.3.6.1.2.1.25.3.3.1.2.1" ->
+            {:ok, 40}
+
+          _ ->
+            {:error, :no_such_object}
+        end
+      end)
+
+      sensors = Cambium.discover_wireless_sensors(@client_opts)
+
+      # Should only have static CPU sensor
+      assert length(sensors) == 1
+      assert hd(sensors).sensor_type == "load"
+    end
+  end
+
+  describe "discover_wireless_sensors/1 - sensor filtering" do
+    test "filters out sensors that fail to respond" do
+      # Mock some sensors succeeding and some failing
+      expect(SnmpMock, :get, fn _, oid, _ ->
+        cond do
+          oid == "1.3.6.1.4.1.17713.21.1.2.32.0" ->
+            {:ok, 1}
+
+          # RSSI responds
+          oid == "1.3.6.1.4.1.17713.21.1.2.3.0" ->
+            {:ok, -68}
+
+          # SNR fails
+          oid == "1.3.6.1.4.1.17713.21.1.2.18.0" ->
+            {:error, :no_such_object}
+
+          # Frequency responds
+          oid == "1.3.6.1.4.1.17713.21.1.2.1.0" ->
+            {:ok, 5200}
+
+          # Clients fails
+          oid == "1.3.6.1.4.1.17713.21.1.2.10.0" ->
+            {:error, :no_such_object}
+
+          # Static CPU sensor
+          oid == "1.3.6.1.2.1.25.3.3.1.2.1" ->
+            {:ok, 50}
+
+          true ->
+            {:error, :no_such_object}
+        end
+      end)
+
+      sensors = Cambium.discover_wireless_sensors(@client_opts)
+
+      # Should have: 1 static + 2 ePMP sensors (RSSI, Freq)
+      assert length(sensors) == 3
+
+      # Should have RSSI and Frequency
+      assert Enum.any?(sensors, &(&1.sensor_type == "rssi" && &1.last_value == -68))
+      assert Enum.any?(sensors, &(&1.sensor_type == "frequency" && &1.last_value == 5200))
+
+      # Should NOT have SNR or clients
+      refute Enum.any?(sensors, &(&1.sensor_type == "snr"))
+      refute Enum.any?(sensors, &(&1.sensor_type == "clients"))
+    end
+  end
+
+  describe "discover_wireless_sensors/1 - edge cases" do
+    test "handles invalid mode value gracefully" do
+      # Mock mode returns invalid value (not 1 or 2)
+      expect(SnmpMock, :get, fn _, oid, _ ->
+        case oid do
+          "1.3.6.1.4.1.17713.21.1.2.32.0" ->
+            {:ok, 99}
+
+          "1.3.6.1.2.1.25.3.3.1.2.1" ->
+            {:ok, 42}
+
+          _ ->
+            {:error, :no_such_object}
+        end
+      end)
+
+      sensors = Cambium.discover_wireless_sensors(@client_opts)
+
+      # Should only have static sensor (invalid mode)
+      assert length(sensors) == 1
+      assert hd(sensors).sensor_type == "load"
+    end
+
+    test "returns empty list when all sensors fail" do
+      expect(SnmpMock, :get, fn _, _, _ ->
+        {:error, :timeout}
       end)
 
       sensors = Cambium.discover_wireless_sensors(@client_opts)