fix(rover-planning): derive grid from lat/lon for coord-only stations

When a user types raw "lat,lon" coordinates into a station input,
LocationResolver populates only `lat` / `lon` — `callsign` and `grid`
stay blank. The path-profiles "Station" cell was falling through to
"33.189, -96.452" instead of showing a useful grid.

Now `station_label/1` (display) and `station_endpoint/1` (path-URL
destination) derive a 6-/8-char Maidenhead grid from the stored
lat/lon when no grid is on the row, matching the rest of the page's
grid-first presentation.

lib/microwaveprop_web/live/rover_planning_live/show.ex

@@ -153,24 +153,36 @@ defmodule MicrowavepropWeb.RoverPlanningLive.Show do
   defp format_meters(nil), do: "—"
   defp format_meters(value) when is_number(value), do: "#{Float.round(value * 1.0, 1)} m"
 
-  defp station_label(%{station: %{callsign: c, grid: g}}) when is_binary(c) and c != "" and is_binary(g) and g != "",
-    do: "#{c} · #{g}"
-
-  defp station_label(%{station: %{callsign: c}}) when is_binary(c) and c != "", do: c
-  defp station_label(%{station: %{grid: g}}) when is_binary(g) and g != "", do: g
-
-  defp station_label(%{station: %{lat: lat, lon: lon}}) when is_number(lat) and is_number(lon),
-    do: "#{Float.round(lat, 3)}, #{Float.round(lon, 3)}"
-
+  # Grid+callsign-first station label. Stations entered as raw lat/lon
+  # have no callsign or grid stored, so derive a 6-char grid from the
+  # coords — that's what the user wants to see, not bare decimals.
+  defp station_label(%{station: %{} = station}), do: station_label_for(station)
   defp station_label(_), do: "—"
 
+  defp station_label_for(%{callsign: c, grid: g}) when is_binary(c) and c != "" and is_binary(g) and g != "",
+    do: "#{c} · #{g}"
+
+  defp station_label_for(%{callsign: c, lat: lat, lon: lon})
+       when is_binary(c) and c != "" and is_number(lat) and is_number(lon),
+       do: "#{c} · #{Maidenhead.from_latlon(lat, lon, 6)}"
+
+  defp station_label_for(%{callsign: c}) when is_binary(c) and c != "", do: c
+  defp station_label_for(%{grid: g}) when is_binary(g) and g != "", do: g
+
+  defp station_label_for(%{lat: lat, lon: lon}) when is_number(lat) and is_number(lon),
+    do: Maidenhead.from_latlon(lat, lon, 6)
+
+  defp station_label_for(_), do: "—"
+
   # Endpoint string used for /path?destination=…. Prefers callsign, then
-  # grid (so PathLive's LocationResolver re-resolves to the same point),
-  # falling back to bare coordinates.
+  # any stored or derived grid (PathLive's LocationResolver re-resolves
+  # both back to the same point), falling back to bare coordinates only
+  # when nothing else is available.
   defp station_endpoint(%{callsign: c}) when is_binary(c) and c != "", do: c
   defp station_endpoint(%{grid: g}) when is_binary(g) and g != "", do: g
 
-  defp station_endpoint(%{lat: lat, lon: lon}) when is_number(lat) and is_number(lon), do: "#{lat},#{lon}"
+  defp station_endpoint(%{lat: lat, lon: lon}) when is_number(lat) and is_number(lon),
+    do: Maidenhead.from_latlon(lat, lon, 8)
 
   defp station_endpoint(_), do: ""
 

test/microwaveprop_web/live/rover_planning_live_test.exs

@@ -88,6 +88,33 @@ defmodule MicrowavepropWeb.RoverPlanningLiveTest do
       assert html =~ grid_10
     end
 
+    test "station label uses derived grid when only lat/lon are stored", %{conn: conn} do
+      user = AccountsFixtures.user_fixture()
+      {:ok, _} = Rover.create_location(user, %{lat: 32.0, lon: -97.0, status: :good})
+
+      # User enters raw coords (no callsign or grid lookup) → station ends
+      # up with lat/lon set but callsign/grid blank.
+      {:ok, mission} =
+        RoverPlanning.create_mission(user, %{
+          "name" => "Coord-only station mission",
+          "band_mhz" => 10_000,
+          "only_known_good" => true,
+          "rover_height_ft" => 8.0,
+          "station_height_ft" => 30.0,
+          "stations" => %{"0" => %{"input" => "33.189,-96.452", "position" => 0}}
+        })
+
+      {:ok, _lv, html} = live(conn, ~p"/rover-planning/#{mission.id}")
+
+      derived = Maidenhead.from_latlon(33.189, -96.452, 6)
+      assert html =~ derived
+      # The path-profiles "Station" cell must render the derived grid,
+      # not the bare lat/lon. Match the exact <td>…</td> shape so we
+      # don't trip on the Stationary-stations list at the top of the
+      # page (which legitimately shows lat/lon as a secondary line).
+      refute html =~ ~s(<td class="font-mono text-xs">33.189, -96.452</td>)
+    end
+
     test "station label shows callsign + grid together when both are known", %{conn: conn} do
       user = AccountsFixtures.user_fixture()
       mission = create_mission(user, "Callsign-grid mission")