Name ACPI hardware IDs instead of magic _HID strings

Turn acpi-ids.zig's flat name table into a HardwareId enum modeled on
ps2-library's Port: one entry() switch holds the registry (variant ->
_HID string + human-readable name), with hid(), description(), and
fromHid() methods. The free description(hid) lookup the kernel's
device-tree dump uses survives, implemented over the enum, and a new
test round-trips every variant through fromHid.

Callers now name the device instead of quoting its id:

- ps2-library's DeviceType.hid() and ps2-bus's descriptor lookups use
  HardwareId.ps2_keyboard / .ps2_mouse.
- device-manager's driverFor parses the HID once with fromHid and
  switches on named values.
- acpi.zig's isPciRootNode carried the same ids twice, as strings and
  as packed-EISA integers (0x030AD041/0x080AD041); both branches now
  decode to the string form and answer through one isPciRootHid helper
  using .pci_bus / .pci_express_root_bridge.
- build.zig threads the acpi-ids module (previously kernel-only) into
  every user binary, like xkeyboard-config.

system/drivers/ps2-bus/ps2-library.zig

@@ -1,6 +1,7 @@
 //! shared definitions between the different PS/2 drivers
 const std = @import("std");
 const runtime = @import("runtime");
+const acpi_ids = @import("acpi-ids");
 const device = runtime.device;
 const system = runtime.system;
 
@@ -261,8 +262,8 @@ pub const DeviceType = enum(u32) {
     /// its command-line argument, or null if we could not classify it.
     pub fn hid(self: DeviceType) ?[]const u8 {
         return switch (self) {
-            .keyboard => "PNP0303",
-            .mouse => "PNP0F13",
+            .keyboard => acpi_ids.HardwareId.ps2_keyboard.hid(),
+            .mouse => acpi_ids.HardwareId.ps2_mouse.hid(),
             .unknown => null,
         };
     }