refactor: constrain captain overview stats range to known windows

enterprise/app/builders/captain/assistant_stats_builder.rb

@@ -9,6 +9,7 @@ class Captain::AssistantStatsBuilder
   RESOLVED_EVENT_NAMES = %w[conversation_captain_inference_resolved conversation_bot_resolved].freeze
   HANDOFF_EVENT_NAMES = %w[conversation_captain_inference_handoff conversation_bot_handoff].freeze
   DEFAULT_RANGE = '30'.freeze
+  ALLOWED_RANGES = %w[7 30 90 this_month last_month].freeze
 
   attr_reader :assistant, :account, :range
 
@@ -18,7 +19,7 @@ class Captain::AssistantStatsBuilder
   def initialize(assistant, range = DEFAULT_RANGE)
     @assistant = assistant
     @account = assistant.account
-    @range = range.presence || DEFAULT_RANGE
+    @range = ALLOWED_RANGES.include?(range.to_s) ? range.to_s : DEFAULT_RANGE
   end
 
   def metrics
@@ -96,8 +97,7 @@ class Captain::AssistantStatsBuilder
     range.to_i.positive? ? range.to_i : 30
   end
 
-  # Combines the per-window message counts and reply time (batched, passed in)
-  # with the reporting-event metrics (resolution and reopen) for one window.
+  # Combines the per-window message counts and reply time with the reporting-event metrics for one window.
   def window_metrics(range, message_counts, avg_reply)
     handled = message_counts[:handled]
     public_count = message_counts[:public_count]

enterprise/app/controllers/api/v1/accounts/captain/assistants_controller.rb

@@ -48,8 +48,8 @@ class Api::V1::Accounts::Captain::AssistantsController < Api::V1::Accounts::Base
   end
 
   def summary
-    result = Rails.cache.fetch(summary_cache_key, expires_in: 1.hour) do
-      builder = Captain::AssistantStatsBuilder.new(@assistant, params[:range])
+    builder = Captain::AssistantStatsBuilder.new(@assistant, params[:range])
+    result = Rails.cache.fetch(summary_cache_key(builder.range), expires_in: 1.hour) do
       Captain::OverviewSummaryService.new(
         account: Current.account,
         assistant: @assistant,
@@ -68,8 +68,8 @@ class Api::V1::Accounts::Captain::AssistantsController < Api::V1::Accounts::Base
 
   private
 
-  def summary_cache_key
-    "captain_overview_summary/#{@assistant.id}/#{params[:range]}/#{Date.current}"
+  def summary_cache_key(range)
+    "captain_overview_summary/#{@assistant.id}/#{range}/#{Date.current}"
   end
 
   def set_assistant