fix: Resolve GenServer errors in tests

- Fix invalid CSS selector in user registration test by replacing
  `fl-contains` with proper href attribute selector
- Disable telemetry database metrics collection in test environment
  to prevent database ownership errors from telemetry poller

This eliminates the GenServer termination errors that were occurring
during test runs due to invalid CSS selectors and database access
issues in background telemetry processes.

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

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

lib/aprsme/telemetry/database_metrics.ex

@@ -125,6 +125,15 @@ defmodule Aprsme.Telemetry.DatabaseMetrics do
   end
 
   def collect_postgres_metrics do
+    # Skip database metrics collection in test environment
+    if Application.get_env(:aprsme, :env) == :test do
+      :ok
+    else
+      do_collect_postgres_metrics()
+    end
+  end
+
+  defp do_collect_postgres_metrics do
     # Database size
     case Aprsme.Repo.query("SELECT pg_database_size(current_database()) as size") do
       {:ok, %{rows: [[size]]}} ->

test/aprsme_web/live/user_registration_live_test.exs

@@ -77,7 +77,7 @@ defmodule AprsmeWeb.UserRegistrationLiveTest do
 
       {:ok, _login_live, login_html} =
         lv
-        |> element(~s|main a:fl-contains("Sign in")|)
+        |> element(~s|main a[href="/users/log_in"]|)
         |> render_click()
         |> follow_redirect(conn, ~p"/users/log_in")