Add live AI checks to system health (#3155)

* Add live AI checks to system health

Give super admins a dedicated AI status view with bounded liveness probes for LLMs, vector stores, pgvector, and embedding endpoints. Record sanitized failures in both the system debug log and Rails logger, and document the recommended local configuration.\n\nCloses #3145

* Fix AI health CI checks

* Address AI health review feedback

* Correct Ollama model preload guidance

* Distinguish OpenAI-compatible providers

* Make Ollama startup readiness explicit

* Recognize Cloudflare AI endpoints

test/system/admin/system_health_test.rb

@@ -0,0 +1,54 @@
+require "application_system_test_case"
+
+class Admin::SystemHealthTest < ApplicationSystemTestCase
+  setup do
+    sign_in users(:sure_support_staff)
+    Setting.stubs(:llm_provider).returns("openai")
+    Setting.stubs(:openai_access_token).returns(nil)
+    Setting.stubs(:openai_uri_base).returns(nil)
+    Setting.stubs(:openai_model).returns(nil)
+    stub_healthy_sidekiq
+    AiHealth::Probe.any_instance.stubs(:llm).returns(probe_result(:passing))
+    AiHealth::Probe.any_instance.stubs(:openai_vector_store).returns(probe_result(:passing))
+  end
+
+  test "selecting AI status runs live probes" do
+    ClimateControl.modify(
+      "OPENAI_ACCESS_TOKEN" => "test-token",
+      "OPENAI_URI_BASE" => nil,
+      "OPENAI_MODEL" => nil,
+      "VECTOR_STORE_PROVIDER" => nil
+    ) do
+      visit admin_system_health_path
+
+      click_button "AI status"
+
+      assert_current_path admin_system_health_path(tab: "ai")
+      assert_selector "button[role='tab'][aria-selected='true']", text: "AI status"
+      assert_text "Live check passed"
+      assert_text "Live checks passed"
+    end
+  end
+
+  private
+    def probe_result(status)
+      AiHealth::Probe::Result.new(
+        status: status,
+        checked_at: Time.current,
+        failure_code: nil,
+        http_status: nil
+      )
+    end
+
+    def stub_healthy_sidekiq
+      SidekiqHealth.any_instance.stubs(:healthy?).returns(true)
+      SidekiqHealth.any_instance.stubs(:processes_count).returns(1)
+      SidekiqHealth.any_instance.stubs(:last_heartbeat_at).returns(Time.current)
+      SidekiqHealth.any_instance.stubs(:max_queue_latency).returns(0.0)
+      SidekiqHealth.any_instance.stubs(:enqueued_count).returns(0)
+      SidekiqHealth.any_instance.stubs(:retry_count).returns(0)
+      SidekiqHealth.any_instance.stubs(:failed_count).returns(0)
+      SidekiqHealth.any_instance.stubs(:processed_count).returns(42)
+      SidekiqHealth.any_instance.stubs(:queue_breakdown).returns([ [ "default", 0, 0.0 ] ])
+    end
+end