reorg: move device-manager-protocol to library/protocol + direct import

device-manager-protocol -> library/protocol/device-manager/. Its consumers
(pci-bus, usb-xhci-bus, the acpi discovery service, device-manager, device-list,
crash-test, and the not-yet-built intel-integrated display sub-driver) import the
module directly instead of through runtime.device_manager_protocol, which is
deleted. runtime.device_manager (the hello client) already imported the module
by name and is unchanged.

zig build + test green; device-manager, driver-restart, device-list, pci-scan pass.

build.zig

@@ -400,7 +400,7 @@ pub fn build(b: *std.Build) void {
     // The device-manager protocol: hello + (M18.2) tree reports, exposed as its
     // own module like the other protocol modules. Imported through the runtime.
     const device_manager_protocol_module = b.addModule("device-manager-protocol", .{
-        .root_source_file = b.path("system/services/device-manager/device-manager-protocol.zig"),
+        .root_source_file = b.path("library/protocol/device-manager/device-manager-protocol.zig"),
     });
     runtime_module.addImport("device-manager-protocol", device_manager_protocol_module);
     // The block protocol, so runtime.block (the block-device client) can speak it.
@@ -551,6 +551,7 @@ pub fn build(b: *std.Build) void {
     const ps2_mouse_exe = addUserBinary(b, kernel_target, runtime_module, mmio_module, xkeyboard_config_module, acpi_ids_module, "ps2-mouse", "system/drivers/ps2-bus/mouse.zig");
     programModule(ps2_mouse_exe).addImport("input-protocol", input_protocol_module);
     const usb_xhci_bus_exe = addUserBinary(b, kernel_target, runtime_module, mmio_module, xkeyboard_config_module, acpi_ids_module, "usb-xhci-bus", "system/drivers/usb-xhci-bus/usb-xhci-bus.zig");
+    programModule(usb_xhci_bus_exe).addImport("device-manager-protocol", device_manager_protocol_module);
     // The xHCI bus driver builds chapter-9 requests and decodes descriptors from
     // usb-abi, and reports each interface's (class,subclass,protocol) identity via
     // usb-ids.packTriple.
@@ -587,13 +588,16 @@ pub fn build(b: *std.Build) void {
     const shared_memory_client_exe = addUserBinary(b, kernel_target, runtime_module, mmio_module, xkeyboard_config_module, acpi_ids_module, "shared-memory-client", "system/services/shared-memory-client/shared-memory-client.zig");
     const fat_test_exe = addUserBinary(b, kernel_target, runtime_module, mmio_module, xkeyboard_config_module, acpi_ids_module, "fat-test", "system/services/fat/fat-test.zig");
     const pci_bus_exe = addUserBinary(b, kernel_target, runtime_module, mmio_module, xkeyboard_config_module, acpi_ids_module, "pci-bus", "system/drivers/pci-bus/pci-bus.zig");
+    programModule(pci_bus_exe).addImport("device-manager-protocol", device_manager_protocol_module);
     // The PCI bus driver decodes each function's class triple to human names in its
     // boot log (class/subclass/prog-IF), so pull in the shared pci-class reference.
     programModule(pci_bus_exe).addImport("pci-class", pci_class_module);
     // A test fixture, not a real driver: hellos to the device manager, then faults —
     // what the driver-restart scenario drives the crash-loop cap with.
     const crash_test_exe = addUserBinary(b, kernel_target, runtime_module, mmio_module, xkeyboard_config_module, acpi_ids_module, "crash-test", "system/services/crash-test/crash-test.zig");
+    programModule(crash_test_exe).addImport("device-manager-protocol", device_manager_protocol_module);
     const device_list_exe = addUserBinary(b, kernel_target, runtime_module, mmio_module, xkeyboard_config_module, acpi_ids_module, "device-list", "system/services/device-list/device-list.zig");
+    programModule(device_list_exe).addImport("device-manager-protocol", device_manager_protocol_module);
     // The discovery service: one swappable process per firmware
     // (docs/discovery.md), bundled under the neutral ramdisk name
     // "discovery" so the device manager never learns which firmware it is on.
@@ -609,9 +613,11 @@ pub fn build(b: *std.Build) void {
     };
     const discovery_exe = addUserBinary(b, kernel_target, runtime_module, mmio_module, xkeyboard_config_module, acpi_ids_module, "discovery", discovery_source);
     if (discovery == .acpi) programModule(discovery_exe).addImport("aml", aml_module);
+    if (discovery == .acpi) programModule(discovery_exe).addImport("device-manager-protocol", device_manager_protocol_module);
     const device_manager_exe = addUserBinary(b, kernel_target, runtime_module, mmio_module, xkeyboard_config_module, acpi_ids_module, "device-manager", "system/services/device-manager/device-manager.zig");
     // Names the xHCI PCI class triple from the shared taxonomy instead of a bare 0x0C0330.
     programModule(device_manager_exe).addImport("pci-class", pci_class_module);
+    programModule(device_manager_exe).addImport("device-manager-protocol", device_manager_protocol_module);
     // The manager matches reported USB interfaces by their (class,subclass,protocol)
     // triple (usbDriverForIdentity), built from the named usb-ids codes.
     programModule(device_manager_exe).addImport("usb-ids", usb_ids_module);