Call super().add_object() in List, Tuple and Object strategies

[gaoflow]

Problem

SchemaStrategy.add_object is a no-op base method, but cooperative subclasses
rely on each strategy's add_object override chaining up through
super().add_object() so their own hooks run. #79 restored this for Number
("added missing super in Number so inheritance would be called") and #82
applied it to the new Enum strategy — but List, Tuple and Object still
override add_object without calling super().

As a result, a cooperative mixin's add_object is silently skipped for arrays,
tuples and objects, while it runs for numbers and enums:

class RecordingMixin(SchemaStrategy):
    log = []
    def add_object(self, obj):
        type(self).log.append(obj)
        super().add_object(obj)

class RecordingObject(Object, RecordingMixin):
    log = []

class B(SchemaBuilder):
    STRATEGIES = (RecordingObject,)

B().add_object({})
# RecordingObject.log == []   -> hook never ran (should be [{}])

Fix

Add the missing super().add_object(obj) call to List, Tuple and Object,
matching Number and Enum. The base method is a no-op, so stock genson
behavior is unchanged; this only completes the cooperative chain for
subclasses.

Tests

TestAddObjectSuperChaining in test/test_custom.py records objects via a
cooperative mixin and asserts the hook fires for List, Tuple and Object
(with Number as the already-fixed control), plus a nested
object → list → object case verifying the hook fires at every level. The array/
tuple/object tests fail before the change and pass after; full suite: 118
passed.