Compiler: Not-identical and not-equal operators (!=, !==) parity in JIT

[PurHur]

Problem

#90 tracks mixed-type equality. Web routing also needs reliable !== and != in JIT for guards like if ($_SERVER['REQUEST_METHOD'] !== 'POST').

Goal

Audit and fix TYPE_IDENTICAL / equality negation in JIT; match VM.

Tasks

• Inventory opcodes for !=, !==, <> in lib/Compiler.php
• VM reference behavior tests
• JIT LLVM lowering fixes
• PHPT compliance + web guard case
• Close gaps found by Compiler: VM/JIT comparison and equality for mixed types (routing guards) #90

Acceptance criteria

JIT and VM agree on edge cases (null, false, '', 0).

Files

• lib/Compiler.php, lib/JIT.php, test/compliance/