feat: migrate PCI and E1000 to HAL driver registry

feat: migrate PCI and E1000 to HAL driver registry

- PCI: hal_driver 'x86-pci' (BUS, priority 10) — self-registers via pci_driver_register()
- E1000: hal_driver 'e1000' (NET, priority 20) — probe checks PCI for Intel 82540EM
- init.c: replace explicit pci_init()/e1000_init() with driver registration + hal_drivers_init_all()
- Drivers init in priority order: PCI bus first, then E1000 probes and inits
- Pattern ready for additional drivers to self-register

20/20 smoke, cppcheck clean