fixed duplicate content-length header in default handler; add base64 dependency

landline.gemspec

@@ -16,4 +16,6 @@ Gem::Specification.new do |spec|
   spec.files                 = Dir["lib/**/*"]
   spec.extra_rdoc_files      = Dir["*.md"]
   spec.required_ruby_version = ">= 3.0.0"
+
+  spec.add_dependency 'base64', '~> 0.3.0'
 end

lib/landline/server.rb

@@ -80,7 +80,6 @@ module Landline
         "handle.default" => proc do |code, backtrace: nil, **_extra|
           page = Landline::Util.default_error_page(code, backtrace)
           headers = {
-            "content-length": page.bytesize,
             "content-type": "text/html",
             "x-cascade": true
           }