reorg: decouple the microkernel from the device taxonomies

The kernel's only dependency on pci-class and acpi-ids was cosmetic: the
boot-time device-tree dump (DeviceTree.dump) decoded class codes and _HID
strings to human names. That is device decoding — a user-space concern in a
microkernel, and the last thing pinning two userspace taxonomies into the
kernel's compile.

dumpNode now prints raw values (the class tag, the raw _HID string, and the
packed PCI class code as hex); a user-space tool that owns the taxonomies
(the device manager already imports them) can pretty-print when wanted. The
pci-class / acpi-ids imports are dropped from device-model.zig and from the
platform module.

The kernel's sole remaining library/device/ import is now device-abi (pure
data — the device-model types the broker marshals across the syscall
boundary), the one intentional kernel->library crossing.

zig build + test green; smoke, discovery, acpi-parse, acpi-ps2 pass.

build.zig

@@ -358,8 +358,6 @@ pub fn build(b: *std.Build) void {
             .{ .name = "boot-handoff", .module = boot_handoff_module }, // BootInformation (carries the ACPI RSDP), physicalToVirtual
             .{ .name = "abi", .module = abi_module }, // acpi.zig works in page_size units
             .{ .name = "device-abi", .module = device_abi_module }, // device-model's DeviceClass/ResourceKind live here
-            .{ .name = "pci-class", .module = pci_class_module }, // decode PCI class codes in the device dump
-            .{ .name = "acpi-ids", .module = acpi_ids_module }, // decode ACPI _HID names in the device dump
             .{ .name = "parameters", .module = parameters_module }, // maximum_cpus (the discovery pool)
         },
     });