fix: Move required tracker_factory kwarg before optional params

Fixes Style/KeywordParametersOrder rubocop offense by placing the
required keyword parameter first in AIConfig#initialize.

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

Author: jsonbailey

lib/server/ai/client.rb

@@ -143,7 +143,7 @@ def to_h
       class AIConfig
         attr_reader :enabled, :messages, :model, :provider
 
-        def initialize(enabled: nil, model: nil, messages: nil, tracker_factory:, provider: nil)
+        def initialize(tracker_factory:, enabled: nil, model: nil, messages: nil, provider: nil)
           @enabled = enabled
           @messages = messages
           @tracker_factory = tracker_factory