Add dialyzer type specs to refactored functions

Added comprehensive type specifications to all recently refactored
functions to improve type safety and enable dialyzer checking:

PollerWorker:
- detect_sensor_changes/3
- extract_thresholds/1
- detect_and_log_changes/4

EquipmentLive.Form:
- extract_snmp_config/1
- normalize_port/1
- test_snmp_connection/1

EquipmentLive.Show:
- seconds_to_weeks/1, seconds_to_days/1
- seconds_to_hours/1, seconds_to_minutes/1
- format_time_part/2

All specs use proper Elixir types and handle nil cases appropriately.

lib/towerops/snmp/poller_worker.ex

@@ -308,6 +308,12 @@ defmodule Towerops.Snmp.PollerWorker do
     end
   end
 
+  @spec detect_and_log_changes(
+          Towerops.Snmp.Interface.t(),
+          map(),
+          Ecto.UUID.t(),
+          DateTime.t()
+        ) :: :ok | nil
   defp detect_and_log_changes(interface, current_attrs, equipment_id, timestamp) do
     events =
       []
@@ -599,6 +605,7 @@ defmodule Towerops.Snmp.PollerWorker do
     end
   end
 
+  @spec detect_sensor_changes(Towerops.Snmp.Sensor.t(), float(), DateTime.t()) :: :ok
   defp detect_sensor_changes(sensor, current_value, timestamp) do
     # Skip change detection if there's no previous value to compare against
     if sensor.last_value == nil do
@@ -616,6 +623,12 @@ defmodule Towerops.Snmp.PollerWorker do
     end
   end
 
+  @spec extract_thresholds(map()) :: %{
+          warning_high: float() | nil,
+          critical_high: float() | nil,
+          warning_low: float() | nil,
+          critical_low: float() | nil
+        }
   defp extract_thresholds(metadata) do
     %{
       warning_high: metadata["warning_high"],

lib/towerops_web/live/equipment_live/form.ex

@@ -180,6 +180,12 @@ defmodule ToweropsWeb.EquipmentLive.Form do
     end
   end
 
+  @spec extract_snmp_config(Phoenix.HTML.Form.t()) :: %{
+          ip_address: String.t() | nil,
+          snmp_community: String.t() | nil,
+          snmp_version: String.t() | nil,
+          snmp_port: integer()
+        }
   defp extract_snmp_config(form) do
     form_data = form.data
     params = form.params
@@ -192,10 +198,17 @@ defmodule ToweropsWeb.EquipmentLive.Form do
     }
   end
 
+  @spec normalize_port(integer() | String.t() | any()) :: integer()
   defp normalize_port(port) when is_integer(port), do: port
   defp normalize_port(port) when is_binary(port), do: String.to_integer(port)
   defp normalize_port(_), do: 161
 
+  @spec test_snmp_connection(%{
+          ip_address: String.t() | nil,
+          snmp_community: String.t() | nil,
+          snmp_version: String.t() | nil,
+          snmp_port: integer()
+        }) :: %{success: boolean(), message: String.t()}
   defp test_snmp_connection(config) do
     case Snmp.test_connection(
            config.ip_address,

lib/towerops_web/live/equipment_live/show.ex

@@ -179,11 +179,19 @@ defmodule ToweropsWeb.EquipmentLive.Show do
     end
   end
 
+  @spec seconds_to_weeks(integer()) :: {integer(), integer()}
   defp seconds_to_weeks(seconds), do: {div(seconds, 604_800), rem(seconds, 604_800)}
+
+  @spec seconds_to_days(integer()) :: {integer(), integer()}
   defp seconds_to_days(seconds), do: {div(seconds, 86_400), rem(seconds, 86_400)}
+
+  @spec seconds_to_hours(integer()) :: {integer(), integer()}
   defp seconds_to_hours(seconds), do: {div(seconds, 3600), rem(seconds, 3600)}
+
+  @spec seconds_to_minutes(integer()) :: {integer(), integer()}
   defp seconds_to_minutes(seconds), do: {div(seconds, 60), rem(seconds, 60)}
 
+  @spec format_time_part(integer(), String.t()) :: String.t() | nil
   defp format_time_part(0, _unit), do: nil
   defp format_time_part(1, unit), do: "1 #{unit}"
   defp format_time_part(count, unit), do: "#{count} #{unit}s"