Language: User-defined constants (const, define()) and class constants

[PurHur]

Problem

Web apps use const VERSION = '1.0';, define('DEBUG', true);, and class constants for config. Support in CFG → opcodes → VM is incomplete or missing.

Goal

const APP_NAME = 'MiniWeb';
define('MAX_UPLOAD', 1024);
class Config { public const ENV = 'prod'; }

Tasks

• Lower Op\Stmt\Const_ and define() calls
• Class const in compileClassBody (extend beyond properties)
• VM constant table + immutable fetches
• JIT: inline literal constants where possible
• PHPT compliance cases

Acceptance criteria

Echo constants from global and class scope in VM and JIT.

Dependencies

• Language: Class methods and property access in JIT #58 class support
• Language: Magic constants __DIR__, __FILE__, __LINE__ for multi-file apps #85 __DIR__ for config paths

Files

• lib/Compiler.php, lib/VM.php, lib/OpCode.php