Round lat/lon to 6 decimals everywhere, add commas to EIRP display

- Round grid-derived lat/lon in maybe_fill_latlon changeset step
- Format lat/lon to 6 decimal places on index table
- Migrate existing beacon data to 6 decimal precision
- Add comma separators to EIRP mW display (e.g. 10,000 mW)
- Extract shared add_commas helper for format_freq and format_mw

lib/microwaveprop/beacons/beacon.ex

@@ -52,11 +52,18 @@ defmodule Microwaveprop.Beacons.Beacon do
   """
   def format_mw(nil), do: ""
 
-  def format_mw(mw) when is_float(mw) do
-    if mw == trunc(mw) do
-      Integer.to_string(trunc(mw))
+  def format_mw(mw) when is_number(mw) do
+    int_part = trunc(mw)
+    frac = mw - int_part
+
+    formatted_int = add_commas(int_part)
+
+    if frac == 0.0 do
+      formatted_int
     else
-      mw |> :erlang.float_to_binary(decimals: 3) |> trim_trailing_zeros()
+      decimal = mw |> :erlang.float_to_binary(decimals: 3) |> trim_trailing_zeros()
+      [_int, frac_part] = String.split(decimal, ".")
+      "#{formatted_int}.#{frac_part}"
     end
   end
 
@@ -69,13 +76,7 @@ defmodule Microwaveprop.Beacons.Beacon do
     int_part = trunc(mhz)
     frac = mhz - int_part
 
-    formatted_int =
-      int_part
-      |> Integer.to_string()
-      |> String.reverse()
-      |> String.replace(~r/.{3}/, "\\0,")
-      |> String.trim_trailing(",")
-      |> String.reverse()
+    formatted_int = add_commas(int_part)
 
     if frac == 0.0 do
       formatted_int
@@ -88,6 +89,15 @@ defmodule Microwaveprop.Beacons.Beacon do
 
   def format_freq(mhz), do: to_string(mhz)
 
+  defp add_commas(int) do
+    int
+    |> Integer.to_string()
+    |> String.reverse()
+    |> String.replace(~r/.{3}/, "\\0,")
+    |> String.trim_trailing(",")
+    |> String.reverse()
+  end
+
   defp trim_trailing_zeros(str) do
     if String.contains?(str, ".") do
       str |> String.trim_trailing("0") |> String.trim_trailing(".")
@@ -217,8 +227,8 @@ defmodule Microwaveprop.Beacons.Beacon do
       case Maidenhead.to_latlon(grid) do
         {:ok, {new_lat, new_lon}} ->
           changeset
-          |> put_change(:lat, new_lat)
-          |> put_change(:lon, new_lon)
+          |> put_change(:lat, Float.round(new_lat * 1.0, 6))
+          |> put_change(:lon, Float.round(new_lon * 1.0, 6))
 
         :error ->
           changeset

lib/microwaveprop_web/live/beacon_live/index.ex

@@ -27,8 +27,8 @@ defmodule MicrowavepropWeb.BeaconLive.Index do
         <:col :let={{_id, beacon}} label="Frequency (MHz)">{Beacon.format_freq(beacon.frequency_mhz)}</:col>
         <:col :let={{_id, beacon}} label="Call">{beacon.callsign}</:col>
         <:col :let={{_id, beacon}} label="Grid">{beacon.grid}</:col>
-        <:col :let={{_id, beacon}} label="Lat">{beacon.lat}</:col>
-        <:col :let={{_id, beacon}} label="Lon">{beacon.lon}</:col>
+        <:col :let={{_id, beacon}} label="Lat">{format_coord(beacon.lat)}</:col>
+        <:col :let={{_id, beacon}} label="Lon">{format_coord(beacon.lon)}</:col>
         <:col :let={{_id, beacon}} label="EIRP (mW)">{Beacon.format_mw(beacon.power_mw)}</:col>
         <:col :let={{_id, beacon}} label="Height AGL (ft)">{beacon.height_ft}</:col>
         <:col :let={{_id, beacon}} label="Keying">{Beacon.keying_label(beacon.keying)}</:col>
@@ -162,4 +162,7 @@ defmodule MicrowavepropWeb.BeaconLive.Index do
 
   defp admin?(%{user: %{is_admin: true}}), do: true
   defp admin?(_), do: false
+
+  defp format_coord(value) when is_float(value), do: :erlang.float_to_binary(value, decimals: 6)
+  defp format_coord(value), do: to_string(value)
 end

priv/repo/migrations/20260411144719_round_beacon_lat_lon_to_6_decimals.exs

@@ -0,0 +1,9 @@
+defmodule Microwaveprop.Repo.Migrations.RoundBeaconLatLonTo6Decimals do
+  use Ecto.Migration
+
+  def up do
+    execute "UPDATE beacons SET lat = ROUND(lat::numeric, 6), lon = ROUND(lon::numeric, 6)"
+  end
+
+  def down, do: :ok
+end