chore(ui,agent): harden collector parsing, drop dead CSS, resilver label

Addresses final code review:
- to_int/1 now returns 0 on nil or unparseable strings instead of crashing
- remove unused .pool-row CSS (superseded by .pool-block)
- clamp capacity bar width to [0, 100] to prevent visual overflow
- pool_scrub_line/1 uses scan_function so resilver shows as "resilver..."

server/lib/server_web/live/host_detail_live.ex

@@ -76,7 +76,7 @@ defmodule ServerWeb.HostDetailLive do
             </div>
 
             <div class="capbar" data-level={capbar_level(pool["capacity_percent"])}>
-              <span style={"width: #{pool["capacity_percent"] || 0}%"}></span>
+              <span style={"width: #{capbar_width(pool["capacity_percent"])}%"}></span>
             </div>
 
             <div class="sizes">
@@ -181,17 +181,29 @@ defmodule ServerWeb.HostDetailLive do
   defp capbar_level(cap) when is_number(cap) and cap >= 80, do: "warn"
   defp capbar_level(_), do: "ok"
 
-  defp pool_scrub_line(%{"scan_state" => "SCANNING"}), do: "scrub scanning"
+  defp capbar_width(cap) when is_number(cap), do: cap |> max(0) |> min(100)
+  defp capbar_width(_), do: 0
 
-  defp pool_scrub_line(%{"scan_state" => "FINISHED", "last_scrub_end" => end_time})
-       when is_binary(end_time) and end_time != "",
-       do: "scrub finished #{end_time}"
+  defp pool_scrub_line(%{"scan_state" => "SCANNING"} = pool) do
+    "#{scan_verb(pool)} scanning"
+  end
 
-  defp pool_scrub_line(%{"last_scrub_end" => end_time}) when is_binary(end_time) and end_time != "",
-    do: "scrub #{end_time}"
+  defp pool_scrub_line(%{"last_scrub_end" => end_time} = pool)
+       when is_binary(end_time) and end_time != "" do
+    prefix =
+      case pool["scan_state"] do
+        "FINISHED" -> "#{scan_verb(pool)} finished "
+        _ -> "#{scan_verb(pool)} "
+      end
+
+    prefix <> end_time
+  end
 
   defp pool_scrub_line(_), do: "scrub never"
 
+  defp scan_verb(%{"scan_function" => "resilver"}), do: "resilver"
+  defp scan_verb(_), do: "scrub"
+
   defp degraded_vdevs(pool) do
     (pool["vdevs"] || [])
     |> Enum.filter(fn v -> Map.get(v, "state") not in [nil, "ONLINE"] end)