fix: log swallowed async task exits in GEFS scoring and HRRR range fetch

GefsFetch silently dropped crashed score-computation tasks via
`{:exit, _reason} -> []`, hiding partial-grid outages from k8s logs.
HRRR range downloads mapped exits to `{:error, reason}` without logging
the URL, so the failing range was lost by the time the caller surfaced
the error.

All three sites now Logger.error with enough context (fh, valid_time,
url) to debug from production logs.

lib/microwaveprop/weather/hrrr_client.ex

@@ -566,8 +566,13 @@ defmodule Microwaveprop.Weather.HrrrClient do
         timeout: 120_000
       )
       |> Enum.map(fn
-        {:ok, result} -> result
-        {:exit, reason} -> {:error, reason}
+        {:ok, result} ->
+          result
+
+        {:exit, reason} ->
+          Logger.error("HRRR grib range download crashed (to_file): url=#{url} reason=#{inspect(reason)}")
+
+          {:error, reason}
       end)
 
     case Enum.find(results, &match?({:error, _}, &1)) do
@@ -612,8 +617,13 @@ defmodule Microwaveprop.Weather.HrrrClient do
         timeout: 120_000
       )
       |> Enum.map(fn
-        {:ok, result} -> result
-        {:exit, reason} -> {:error, reason}
+        {:ok, result} ->
+          result
+
+        {:exit, reason} ->
+          Logger.error("HRRR grib range download crashed: url=#{url} reason=#{inspect(reason)}")
+
+          {:error, reason}
       end)
 
     # Sort by offset and concatenate

lib/microwaveprop/workers/gefs_fetch_worker.ex

@@ -172,8 +172,15 @@ defmodule Microwaveprop.Workers.GefsFetchWorker do
         timeout: 30_000
       )
       |> Stream.flat_map(fn
-        {:ok, results} -> results
-        {:exit, _reason} -> []
+        {:ok, results} ->
+          results
+
+        {:exit, reason} ->
+          Logger.error(
+            "GefsFetch scoring task crashed: fh=#{fh} valid_time=#{inspect(valid_time)} reason=#{inspect(reason)}"
+          )
+
+          []
       end)
       |> Enum.to_list()