Decode ACPI _HID names in device discovery

The flat analog of pci-class for acpi_device nodes. ACPI has no class/subclass/prog-IF
taxonomy — a device's identity is its _HID string itself (PNP0303 *is* "PS/2
keyboard") — so this is a plain id -> name registry, not a hierarchical decoder.

New system/devices/acpi-ids.zig (module `acpi-ids`): the common standard PnP/ACPI
hardware IDs; vendor-specific ids (QEMU0002, etc.) have no registry name and print the
raw HID. Shared reference data like pci-class. The dump now names each _HID:

    KBD_ [acpi_device] hid=PNP0303 (PS/2 Keyboard)
    COM1 [acpi_device] hid=PNP0501 (16550A-compatible Serial Port)
    RTC_ [acpi_device] hid=PNP0B00 (Real-Time Clock (RTC))
    LNKA [acpi_device] hid=PNP0C0F (PCI Interrupt Link Device)
    FWCF [acpi_device] hid=QEMU0002          (vendor-specific: raw HID)

Host test covers known ids and the unknown/empty fallthrough. Suite 41/41 plus host
tests.

build.zig

@@ -121,6 +121,11 @@ pub fn build(b: *std.Build) void {
     const pci_class_module = b.addModule("pci-class", .{
         .root_source_file = b.path("system/devices/pci-class.zig"),
     });
+    // ACPI/PnP hardware-ID (_HID) names — the flat analog of pci-class for acpi_device
+    // nodes. Also shared reference data.
+    const acpi_ids_module = b.addModule("acpi-ids", .{
+        .root_source_file = b.path("system/devices/acpi-ids.zig"),
+    });
 
     // Kernel tunables (maximum_cpus, stack sizes, tick rate). A dependency-free module of
     // compile-time constants, imported wherever a knob is read; keeps the trade-offs
@@ -159,6 +164,7 @@ pub fn build(b: *std.Build) void {
             .{ .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)
         },
     });
@@ -446,6 +452,7 @@ pub fn build(b: *std.Build) void {
         "system/abi.zig",
         "system/devices/device-abi.zig",
         "system/devices/pci-class.zig", // class/subclass/prog-IF name decoding
+        "system/devices/acpi-ids.zig", // _HID name decoding
         "library/mmio/mmio.zig", // barriers assemble + registers round-trip
     }) |root| {
         const mod_tests = b.addTest(.{