refactor: Remove unused valid_active_span?/0 public function

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: Jez-A

lib/zexbox/open_telemetry.ex

@@ -23,17 +23,6 @@ defmodule Zexbox.OpenTelemetry do
   @grafana_host "zappi.grafana.net"
   @kibana_host "zappi.tools"
 
-  @doc "Returns `true` when the current OTEL span context is valid (non-zero trace ID)."
-  @spec valid_active_span?() :: boolean()
-  def valid_active_span? do
-    case get_span_context() do
-      nil -> false
-      context -> :otel_span.is_valid(context)
-    end
-  rescue
-    _e -> false
-  end
-
   @doc """
   Returns a Grafana Tempo trace URL for the current span, or `nil` if no active span
   or if the environment is not `:production` or `:sandbox`.

test/zexbox/open_telemetry_test.exs

@@ -39,26 +39,6 @@ defmodule Zexbox.OpenTelemetryTest do
     :ok
   end
 
-  describe "valid_active_span?/0" do
-    test "returns true when the current span is valid" do
-      with_active_span(fn ->
-        assert OpenTelemetry.valid_active_span?() == true
-      end)
-    end
-
-    test "returns false when there is no active span" do
-      with_no_span(fn ->
-        assert OpenTelemetry.valid_active_span?() == false
-      end)
-    end
-
-    test "returns false when OTEL raises" do
-      with_mock :otel_tracer, current_span_ctx: fn -> raise "otel not running" end do
-        assert OpenTelemetry.valid_active_span?() == false
-      end
-    end
-  end
-
   describe "generate_trace_url/0" do
     test "returns nil when there is no active span" do
       Application.put_env(:zexbox, :app_env, :production)