refactor: Replace @tracked_* booleans with @summary nil checks

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

Author: jsonbailey

lib/server/ai/ai_config_tracker.rb

@@ -67,11 +67,6 @@ def initialize(ld_client:, variation_key:, config_key:, version:, model_name:, p
           @context = context
           @summary = MetricSummary.new
           @run_id = run_id
-          @tracked_duration = false
-          @tracked_time_to_first_token = false
-          @tracked_tokens = false
-          @tracked_success = nil
-          @tracked_feedback = false
           @logger = LaunchDarkly::Server::AI.default_logger
         end
 
@@ -124,11 +119,10 @@ def self.from_resumption_token(token:, ld_client:, context:)
         # @param duration [Integer] The duration in milliseconds
         #
         def track_duration(duration)
-          if @tracked_duration
+          unless @summary.duration.nil?
             @logger&.warn("Duration has already been tracked for this execution.")
             return
           end
-          @tracked_duration = true
           @summary.duration = duration
           @ld_client.track(
             '$ld:ai:duration:total',
@@ -158,11 +152,10 @@ def track_duration_of(&block)
         # @param duration [Integer] The duration in milliseconds
         #
         def track_time_to_first_token(time_to_first_token)
-          if @tracked_time_to_first_token
+          unless @summary.time_to_first_token.nil?
             @logger&.warn("Time to first token has already been tracked for this execution.")
             return
           end
-          @tracked_time_to_first_token = true
           @summary.time_to_first_token = time_to_first_token
           @ld_client.track(
             '$ld:ai:tokens:ttf',
@@ -178,11 +171,10 @@ def track_time_to_first_token(time_to_first_token)
         # @param kind [Symbol] The kind of feedback (:positive or :negative)
         #
         def track_feedback(kind:)
-          if @tracked_feedback
+          unless @summary.feedback.nil?
             @logger&.warn("Feedback has already been tracked for this execution.")
             return
           end
-          @tracked_feedback = true
           @summary.feedback = kind
           event_name = kind == :positive ? '$ld:ai:feedback:user:positive' : '$ld:ai:feedback:user:negative'
           @ld_client.track(
@@ -197,11 +189,10 @@ def track_feedback(kind:)
         # Track a successful AI generation
         #
         def track_success
-          unless @tracked_success.nil?
+          unless @summary.success.nil?
             @logger&.warn("Success or error has already been tracked for this execution.")
             return
           end
-          @tracked_success = true
           @summary.success = true
           @ld_client.track(
             '$ld:ai:generation:success',
@@ -215,11 +206,10 @@ def track_success
         # Track an error in AI generation
         #
         def track_error
-          unless @tracked_success.nil?
+          unless @summary.success.nil?
             @logger&.warn("Success or error has already been tracked for this execution.")
             return
           end
-          @tracked_success = false
           @summary.success = false
           @ld_client.track(
             '$ld:ai:generation:error',
@@ -235,11 +225,10 @@ def track_error
         # @param token_usage [TokenUsage] An object containing token usage details
         #
         def track_tokens(token_usage)
-          if @tracked_tokens
+          unless @summary.usage.nil?
             @logger&.warn("Tokens have already been tracked for this execution.")
             return
           end
-          @tracked_tokens = true
           @summary.usage = token_usage
           if token_usage.total.positive?
             @ld_client.track(