🚚 Compile Config[:defaults] in AttrVersionDefaults

This avoids usage of the private `Config#defaults_hash` method, relying
instead on the public `#load_defaults` API.

Author: nevans

lib/net/imap/config.rb

@@ -482,8 +482,6 @@ def defaults_hash
 
       @global = default.new
 
-      version_defaults[:default] = default.send(:defaults_hash)
-
       version_defaults[0r] = {
         sasl_ir: false,
         responses_without_block: :silence_deprecation_warning,

lib/net/imap/config/attr_version_defaults.rb

@@ -38,7 +38,10 @@ module AttrVersionDefaults
         # :stopdoc: internal APIs only
 
         def self.compile_version_defaults!
-          version_defaults[:default] = Config[version_defaults[:default]]
+          # Temporarily assign Config.default, enabling #load_defaults(:default)
+          version_defaults[:default] = Config.default
+          # Use #load_defaults so some attributes are inherited from global.
+          version_defaults[:default] = Config.new.load_defaults(:default).freeze
           version_defaults[0.0r]     = Config[:default].dup
             .update(**version_defaults[0.0r]).freeze