Add TOKEN_PIPEPIPE token for '||' syntax, implement or() parsing function with CODE_OR bytecode, and add VM interpreter logic that short-circuits on truthy left operand. Update .gitignore to exclude *.xccheckout files, extend test coverage for falsy behavior in and.wren and if.wren, and add comprehensive or.wren test suite verifying short-circuit semantics and truthiness rules.
Introduce Scope struct and PUSH_SCOPE/POP_SCOPE macros to manage nested variable scopes during compilation. Update declareVariable to distinguish global declarations from local ones based on scope presence rather than parent compiler. Add truncateSymbolTable helper to clean up local symbols when exiting a scope. Include new test files verifying scoped variable isolation in if, while, and block constructs.
Add TOKEN_WHILE to the token enum and keyword lookup in the compiler, enabling the parser to recognize 'while' statements. Introduce the CODE_LOOP opcode in the VM for backward jumps, and implement the patchJump helper to resolve forward jump offsets during compilation. Include comprehensive test cases for while loops covering single-expression bodies, block bodies, newline handling, and null result semantics.
