* fix(parser): always parenthesize the unary minus operand
Unary minus concatenated '-' directly onto the operand's generated C++.
For a compound operand the minus then bound to the wrong subexpression:
PHP's -($a ? $b : $c) emitted `-cond ? b : c`, which C++ parses as
`(-cond) ? b : c` — the negation lands on the condition and the branch
choice itself can flip (pick(1,2,3) returned 2 instead of -2). The
previous str_starts_with('-') guard only covered operands already
beginning with '-' (the `--` token-pasting case).
Emit '-(' operand ')' unconditionally; this subsumes the pre-decrement
guard. Unary '+' emits no operator text and boolean/bitwise not already
close their operands, so they are unaffected.
* test(operator): accept parenthesized negative infinity literal
parseUnaryMinus now always parenthesizes its operand, so the -INF
float literal is emitted as -(std::numeric_limits<double>::infinity()).
The C++ value is unchanged; only the spelling assertion needed updating.
* fix(parser): keep bare numeric literals unparenthesized under unary minus
A single-token numeric literal cannot change the C++ parse; emitting
-7L directly keeps the generated code and the existing test snapshots
readable. Every other operand stays parenthesized.