Read the gem version from Facets::VERSION

The version was kept twice, in facets.gemspec and in
lib/core/facets/version.rb. The gemspec now requires version.rb and
uses Facets::VERSION, so a release changes one line. The Rakefile
already reads it there too.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01E2Njj4j1r9twkVcXsMySLW

Author: claude

HISTORY.md

@@ -76,6 +76,8 @@ Changes:
     `Assembly` (Detroit), `.index`, `Indexfile` and `lib/core/facets.yml`.
     The Rakefile takes its version from `Facets::VERSION` (`.index` still said
     3.1.1), and `rake package` no longer needs the `mast` and `index` tools.
+  * The gemspec reads its version from `Facets::VERSION`, so the version now
+    lives in one place, `lib/core/facets/version.rb`.
   * Fix the qed demos, which had 8 failures and 2 errors. Most were stale
     expectations (`Array#from`, `#step`, `#arrange`, `String#similarity`)
     and the date demo held pasted irb output.

facets.gemspec

@@ -1,6 +1,8 @@
+require_relative 'lib/core/facets/version'
+
 Gem::Specification.new do |s|
   s.name        = 'facets'
-  s.version     = '3.2.2'
+  s.version     = Facets::VERSION
   s.summary     = 'The premier collection of extension methods for Ruby.'
   s.description = 'Facets is the premier collection of extension methods for the Ruby ' \
                   'programming language. Facets extensions are unique by virtue of their ' \