feat: validate config

lib/mv/config.ex

@@ -85,5 +85,35 @@ defmodule Mv.Config do
   defp get_csv_import_config(key, default) do
     Application.get_env(:mv, :csv_import, [])
     |> Keyword.get(key, default)
+    |> parse_and_validate_integer(default)
+  end
+
+  # Parses and validates integer configuration values.
+  #
+  # Accepts:
+  # - Integer values (passed through)
+  # - String integers (e.g., "1000") - parsed to integer
+  # - Invalid values (e.g., "abc", nil) - falls back to default
+  #
+  # Always clamps the result to a minimum of 1 to ensure positive values.
+  #
+  # Note: We don't log warnings for unparseable values because:
+  # - These functions may be called frequently (e.g., on every request)
+  # - Logging would create excessive log spam
+  # - The fallback to default provides a safe behavior
+  # - Configuration errors should be caught during deployment/testing
+  defp parse_and_validate_integer(value, _default) when is_integer(value) do
+    max(1, value)
+  end
+
+  defp parse_and_validate_integer(value, default) when is_binary(value) do
+    case Integer.parse(value) do
+      {int, _remainder} -> max(1, int)
+      :error -> default
+    end
+  end
+
+  defp parse_and_validate_integer(_value, default) do
+    default
   end
 end