feat: add usage tracking to config method

- Add tracking call for :ai:config:function:single event
- Include test to verify tracking functionality
- Follows SDK spec requirement 1.2.3.5

Co-Authored-By: [email protected] <[email protected]>

Author: devin-ai-integration[bot]

lib/server/ai/client.rb

@@ -147,6 +147,8 @@ def initialize(ld_client)
         # @return [AIConfig] An AIConfig instance containing the configuration data
         #
         def config(config_key, context, default_value = nil, variables = nil)
+          @ld_client.track('$ld:ai:config:function:single', context, config_key, 1)
+
           variation = @ld_client.variation(
             config_key,
             context,

spec/server/ai/config_tracker_spec.rb

@@ -377,4 +377,28 @@
       )
     end
   end
+
+  describe 'config method tracking' do
+    it 'calls track with correct parameters when config is called' do
+      allow(ld_client).to receive(:track)
+      allow(ld_client).to receive(:variation).and_return({
+        '_ldMeta' => { 'enabled' => true, 'variationKey' => 'test-variation', 'version' => 1 },
+        'model' => { 'name' => 'test-model' },
+        'provider' => { 'name' => 'test-provider' },
+        'messages' => []
+      })
+
+      client = LaunchDarkly::Server::AI::Client.new(ld_client)
+      default_value = LaunchDarkly::Server::AI::AIConfig.new(enabled: false)
+      
+      client.config('test-config-key', context, default_value)
+
+      expect(ld_client).to have_received(:track).with(
+        '$ld:ai:config:function:single',
+        context,
+        'test-config-key',
+        1
+      )
+    end
+  end
 end