Generate llms.txt at build time via assets:precompile

Move llms.txt from a committed static file to build-time generation.
The rake task hooks into assets:precompile so Heroku and Docker builds
produce it automatically. No manual step needed on deploy.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: dariye

.gitignore

@@ -26,6 +26,7 @@
 !/tmp/storage/.keep
 
 /public/assets
+/public/llms.txt
 
 # Ignore master key for decrypting credentials and more.
 /config/master.key

app/views/docs/getting_started/llms_txt.rb

@@ -42,7 +42,9 @@ def view_template
       div(class: "space-y-4") do
         Heading(level: 2) { "Keeping it updated" }
         Text do
-          plain "The llms.txt file is generated from the doc source files. If you're contributing to RubyUI, you can regenerate it with:"
+          plain "The llms.txt file is auto-generated during every deploy as part of "
+          InlineCode { "assets:precompile" }
+          plain ". To regenerate locally:"
         end
         Codeblock("rake llms:generate", syntax: :bash)
         Text do

lib/tasks/llms_txt.rake

@@ -23,3 +23,10 @@ namespace :llms do
     puts "Generated #{output_path} (#{count} components)"
   end
 end
+
+# Auto-generate llms.txt during assets:precompile (Heroku & Docker builds)
+if Rake::Task.task_defined?("assets:precompile")
+  Rake::Task["assets:precompile"].enhance do
+    Rake::Task["llms:generate"].invoke
+  end
+end