feat: add symbol removal support in scheme compiler

[mufeedvh]

Summary

• Adds Ruby support for symbol removal functionality
• Implements removal methods for all symbol types with accept conditions
• Provides examples and test cases

Changes

• Added FFI binding for vm_remove_tokens in varnamruby.rb
• Added _remove_token base method and specific removal methods in compile-scheme.rb:
  • remove_vowels
  • remove_consonants
  • remove_consonant_vowel_combinations
  • remove_anusvara
  • remove_visarga
  • remove_virama
  • remove_symbols
  • remove_numbers
  • remove_others
• Added test examples in test/removal.rb
• Added Malayalam scheme example demonstrating the feature

Usage

# Remove 'മ്' at the end of words for pattern 'm'
remove_anusvara({:accept_if => :ends_with}, "m" => ["മ്"])

# Remove specific consonants at start
remove_consonants({:accept_if => :starts_with}, "ka" => ["ക"])

# Remove vowel signs in between words
remove_vowels({:accept_if => :in_between}, "a" => ["ാ"])

Dependencies

• Requires feat: add symbol removal API with accept conditions govarnam#68 to be merged first

Test plan

• Ruby syntax validation tests added
• Example scheme created
• Integration testing with actual VST compilation

Related to varnamproject/govarnam#23