Stdlib: implement stream_isatty() with VM + JIT/AOT lowering (#6035)

[PurHur]

Summary

• Implements stream_isatty() per php-src ext/standard/streamsfuncs.c — TTY detection for stream resources
• PHP implementation in ext/standard/stream_isatty.php + VmFs::streamIsatty(); thin C ABI __compiler_stream_isatty in phpc_stream.c using isatty(fileno(fp)) for AOT/JIT
• Enum case and non-resource operands throw TypeError via shared VmStreamArg::requireStreamHandle guards (php-src-strict)

Closes #6035

php-src reference

• ext/standard/streamsfuncs.c — PHP_FUNCTION(stream_isatty)
• main/streams/php_stream.c — php_stream_isatty()

Verification

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh && vendor/bin/phpunit --filter stream_isatty'
# OK (5 tests, 5 assertions) — VM + JIT + AOT compliance PHPTs

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh && php bin/vm.php test/repro/stream_isatty_6035.php'
# 1\n0

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh && php bin/compile.php -l test/repro/stream_isatty_6035.php'
# OK (AOT lint)

Test plan

• stream_isatty.phpt — function_exists + false on php://memory and plainfile
• stream_isatty_enum_typeerror.phpt — enum case → TypeError naming enum class
• stream_isatty_typeerror.phpt — array operand → TypeError
• Capability matrix updated (stream_isatty | yes | yes | yes)

Made with Cursor