Apply PSR-12 coding standard fixes (elseif, new(), visibility, modifier order, short type keywords)

[lacatoire]

Summary

Apply PSR-12 fixes across the codebase:

• Replace else if → elseif.
• Ensure class instantiations always use parentheses: new Foo() even with no args.
• Add explicit visibility to properties, methods, and constants.
• Fix modifier order: abstract/final → visibility → static.
• Enforce short type keywords per PSR-12: bool (not boolean), int (not integer), float (not double/real), string, array, object, callable, iterable, null.

Motivation

Improves readability and PSR-12 compliance. No functional changes.

Impact

• ✅ No behavior change / BC break.
• ✅ Pure style/consistency.

Examples

Before:
else if ($ok) { … }
new Foo;
final static public function run() {}
/** @param integer $n @return boolean */
private const FOO = 1;

After:
elseif ($ok) { … }
new Foo();
final public static function run(): void {}
/** @param int $n @return bool */
public const FOO = 1;

Reference

• PSR-12: https://www.php-fig.org/psr/psr-12/