chore: Configure YARD documentation generation options

- Add .yardopts file to customize YARD documentation generation
- Exclude private files and set documentation generation preferences
- Adjust YARD visibility annotation in ta_lib_ffi.rb

Author: Youngv

.yardopts

@@ -0,0 +1,3 @@
+--no-private
+--exclude lib/ta_lib_ffi/doc.rb
+lib/**/*.rb

lib/ta_lib_ffi.rb

@@ -22,8 +22,8 @@ module TALibFFI
 
   if defined?(Zeitwerk)
     # https://github.com/fxn/zeitwerk?tab=readme-ov-file#custom-inflector
+    # @!visibility private
     class Inflector < Zeitwerk::GemInflector
-      # @!visibility private
       def camelize(basename, _abspath)
         case basename
         when "ta_lib_ffi"