feat(contact-detail): use 10 GHz threshold for MHz/GHz band display

Anything below 10 GHz now renders in MHz so 2304/3456/5760 etc. match
amateur microwave convention. 10 GHz and above still render in GHz.

lib/microwaveprop_web/live/contact_live/show.ex

@@ -1473,7 +1473,7 @@ defmodule MicrowavepropWeb.ContactLive.Show do
   defp format_band(band) do
     mhz = Decimal.to_float(band)
 
-    if mhz < 1000 do
+    if mhz < 10_000 do
       if mhz == Float.round(mhz, 0) do
         "#{trunc(mhz)} MHz"
       else

test/microwaveprop_web/live/contact_live_test.exs

@@ -150,14 +150,13 @@ defmodule MicrowavepropWeb.ContactLiveTest do
       assert render(lv) =~ contact.station1
     end
 
-    # Band display on the detail page: below 1 GHz renders in MHz, at/above
-    # 1 GHz renders in GHz. Amateur band labels match the unit operators use
-    # in QSO logs — you work 432 MHz, you work 10 GHz.
-    test "renders sub-GHz bands in MHz", %{conn: conn} do
+    # Band display on the detail page: below 10 GHz renders in MHz, at/above
+    # 10 GHz renders in GHz. Amateur microwave convention — 2304 is "2304",
+    # 3456 is "3456", 5760 is "5760", not "2.3 GHz" etc.
+    test "renders sub-10-GHz bands in MHz", %{conn: conn} do
       contact = create_contact(%{band: Decimal.new("432")})
       {:ok, _lv, html} = live(conn, ~p"/contacts/#{contact.id}")
       assert html =~ "432 MHz"
-      refute html =~ "0.4 GHz"
     end
 
     test "renders 50 MHz in MHz", %{conn: conn} do
@@ -166,16 +165,30 @@ defmodule MicrowavepropWeb.ContactLiveTest do
       assert html =~ "50 MHz"
     end
 
-    test "renders GHz bands in GHz", %{conn: conn} do
+    test "renders 1296 MHz in MHz", %{conn: conn} do
+      contact = create_contact(%{band: Decimal.new("1296")})
+      {:ok, _lv, html} = live(conn, ~p"/contacts/#{contact.id}")
+      assert html =~ "1296 MHz"
+      refute html =~ "1.3 GHz"
+    end
+
+    test "renders 2304 MHz in MHz", %{conn: conn} do
+      contact = create_contact(%{band: Decimal.new("2304")})
+      {:ok, _lv, html} = live(conn, ~p"/contacts/#{contact.id}")
+      assert html =~ "2304 MHz"
+      refute html =~ "2.3 GHz"
+    end
+
+    test "renders 10 GHz in GHz (threshold)", %{conn: conn} do
       contact = create_contact(%{band: Decimal.new("10000")})
       {:ok, _lv, html} = live(conn, ~p"/contacts/#{contact.id}")
       assert html =~ "10 GHz"
     end
 
-    test "renders 1296 MHz as 1.3 GHz (above the 1 GHz threshold)", %{conn: conn} do
-      contact = create_contact(%{band: Decimal.new("1296")})
+    test "renders 24 GHz in GHz", %{conn: conn} do
+      contact = create_contact(%{band: Decimal.new("24000")})
       {:ok, _lv, html} = live(conn, ~p"/contacts/#{contact.id}")
-      assert html =~ "1.3 GHz"
+      assert html =~ "24 GHz"
     end
 
     test "raises for bad UUID", %{conn: conn} do