feat: reclaim response_bot flag for custom_tools (#13897)

Repurpose the deprecated response_bot feature flag slot for
custom_tools.

Migration disables the flag on any accounts that had response_bot
enabled so the repurposed slot starts in its default-off state.

Pre-deploy: run the disable script on production using the old flag name
(response_bot) before deploying this migration.

config/features.yml

@@ -104,10 +104,10 @@
   display_name: Audit Logs
   enabled: false
   premium: true
-- name: response_bot
-  display_name: Response Bot
+- name: custom_tools
+  display_name: Custom Tools
   enabled: false
-  deprecated: true
+  premium: true
 - name: message_reply_to
   display_name: Message Reply To
   enabled: false

db/migrate/20260324102005_repurpose_response_bot_flag_for_custom_tools.rb

@@ -0,0 +1,22 @@
+class RepurposeResponseBotFlagForCustomTools < ActiveRecord::Migration[7.1]
+  def up
+    # The response_bot flag (deprecated) has been renamed to custom_tools.
+    # Disable it on any accounts that had response_bot enabled so the repurposed
+    # flag starts in its intended default-off state.
+    Account.feature_custom_tools.find_each(batch_size: 100) do |account|
+      account.disable_features(:custom_tools)
+      account.save!(validate: false)
+    end
+
+    # Remove the stale response_bot entry from ACCOUNT_LEVEL_FEATURE_DEFAULTS.
+    # ConfigLoader only adds new flags; it never removes renamed ones.
+    # Leaving it would cause NoMethodError in enable_default_features when
+    # creating new accounts (feature_response_bot= no longer exists).
+    config = InstallationConfig.find_by(name: 'ACCOUNT_LEVEL_FEATURE_DEFAULTS')
+    return if config&.value.blank?
+
+    config.value = config.value.reject { |f| f['name'] == 'response_bot' }
+    config.save!
+    GlobalConfig.clear_cache
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[7.1].define(version: 2026_03_20_074636) do
+ActiveRecord::Schema[7.1].define(version: 2026_03_24_102005) do
   # These extensions should be enabled to support this database
   enable_extension "pg_stat_statements"
   enable_extension "pg_trgm"