fix(utilities): concurrent first access to lazy protocol exports deadlocks the import system #2771

Describe the bug
Since #2757, threads that reach different lazy exports of pcapkit.protocols at the same time on a cold import deadlock the import system: _DeadlockError: deadlock detected by _ModuleLock('pcapkit.protocols.link.arp.data'). 1.5.1 imported these eagerly, so this is a regression on main. Reaching a single name from many threads does not trigger it.

Reproduction

import threading, pcapkit.protocols as P
names = P.__all__[:16]; b = threading.Barrier(len(names)); errs = []
def go(n):
    b.wait()
    try: getattr(P, n)
    except BaseException as e: errs.append(repr(e))
ts = [threading.Thread(target=go, args=(n,)) for n in names]; [t.start() for t in ts]; [t.join() for t in ts]
print(errs[:1])   # _DeadlockError ... in 19 of 20 fresh processes at 8c30106c7

Expected behavior
Concurrent first access resolves every name, as the eager 1.5.1 imports did.

Additional context
The threads take per-module import locks in different orders, and the protocol/schema/data modules import each other. A likely fix is to serialise first resolution in the shared pcapkit.utilities.importlib.lazy_exports hook, rather than per package. The #2757 thread test only raced on the registry.