fix(frenchtojd): range-check zend_long args before narrowing to int

[lacatoire]

Summary

FrenchToSdn() in ext/calendar/french.c takes C int parameters. PHP_FUNCTION(frenchtojd) parses into zend_long but passes them directly to FrenchToSdn(), causing implicit narrowing. Values whose low 32 bits alias into the valid range (e.g. month = 1 + 2**32) bypass the guard in french.c and return a valid-looking Julian Day instead of 0.

Fix

Add an explicit range check against the zend_long variables in PHP_FUNCTION(frenchtojd), before the call to FrenchToSdn(), mirroring the guard that already exists inside the helper:

if (year < 1 || year > 14 || month < 1 || month > 13 || day < 1 || day > 30) {
    RETURN_LONG(0);
}
RETURN_LONG(FrenchToSdn(year, month, day));

Valid inputs and already-out-of-range values (no aliasing) are unaffected.

Test added

ext/calendar/tests/frenchtojd_overflow.phpt covers the three aliased-overflow cases (month, day, year each + 2**32) and confirms a valid call still returns the correct Julian Day.