fix: Resolve infinite "loading historical data" issue

Fix the issue where the historical data loading indicator would get stuck
indefinitely when no packets are found for a callsign or time period.

Changes:
- Handle empty packet results by properly updating loading state
- Add failsafe timeout (30s) to prevent infinite loading states
- Add debug logging to help identify when no packets are found
- Ensure loading progress is updated even when batches return no data

This fixes the issue where viewing callsigns with no recent data would
show "loading historical data" forever.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

lib/aprsme_web/live/map_live/historical_loader.ex

@@ -49,6 +49,9 @@ defmodule AprsmeWeb.MapLive.HistoricalLoader do
     # Cancel any pending batch tasks
     socket = cancel_pending_loads(socket)
 
+    # Add a failsafe timeout to prevent infinite loading
+    Process.send_after(self(), {:historical_loading_timeout, new_generation}, 30_000)
+
     # For high zoom levels, load everything in one batch for maximum speed
     zoom = socket.assigns.map_zoom || 5
 
@@ -210,7 +213,24 @@ defmodule AprsmeWeb.MapLive.HistoricalLoader do
 
         process_loaded_packets(socket, historical_packets, packet_data_list, batch_offset)
       else
-        socket
+        # No packets found - handle this as a completed batch to prevent infinite loading
+        require Logger
+
+        Logger.debug(
+          "No historical packets found for batch #{batch_offset}, hours_back: #{Map.get(socket.assigns, :historical_hours, "1")}, callsign: #{Map.get(socket.assigns, :tracked_callsign, "")}"
+        )
+
+        total_batches = socket.assigns.total_batches || 1
+        is_final_batch = batch_offset >= total_batches - 1
+
+        # Update progress for user feedback
+        socket = assign(socket, :loading_batch, batch_offset + 1)
+
+        # Mark loading as complete if this was the final batch or if we're doing single-batch loading
+        socket = update_loading_status(socket, is_final_batch)
+
+        # Process any pending bounds update if loading is complete
+        handle_pending_bounds(socket, is_final_batch)
       end
     end
   end

lib/aprsme_web/live/map_live/index.ex

@@ -872,6 +872,25 @@ defmodule AprsmeWeb.MapLive.Index do
     end
   end
 
+  def handle_info({:historical_loading_timeout, generation}, socket) do
+    # Only process if generation matches current loading generation and we're still loading
+    if generation == socket.assigns.loading_generation && socket.assigns.historical_loading do
+      require Logger
+
+      Logger.warning("Historical loading timeout reached, forcing completion")
+
+      socket =
+        socket
+        |> assign(:historical_loading, false)
+        |> assign(:loading_batch, socket.assigns.total_batches || 1)
+
+      {:noreply, socket}
+    else
+      # Stale timeout or already completed, ignore it
+      {:noreply, socket}
+    end
+  end
+
   def handle_info(%Broadcast{topic: "aprs_messages", event: "packet", payload: packet}, socket),
     do: handle_info({:postgres_packet, packet}, socket)