boot: fix ramdisk paths lost to FAT name uppercasing; widen driver-name buffers

The EFI loader now ENUMERATES /system rather than opening files by name,
so the on-disk name must be exact, not merely case-insensitively
findable. make-fat-image.py stored 8.3-fitting lowercase names as bare
uppercase short entries ('init' -> INIT), garbling the ramdisk paths;
now any name whose case the 8.3 entry cannot reproduce gets a long-name
chain carrying the exact name.

device-manager's driver table stored names in 24 bytes — silently
truncating '/system/drivers/usb-xhci-bus' and failing the spawn; widen
to 64 (= abi.maximum_process_name). The usb-report harness regex learns
that restart lines name drivers by path.

system/services/device-manager/device-manager.zig

@@ -132,7 +132,7 @@ const DriverState = enum {
 
 const Driver = struct {
     used: bool = false,
-    name_buffer: [24]u8 = undefined,
+    name_buffer: [64]u8 = undefined, // fits a full binary path (abi.maximum_process_name)
     name_len: usize = 0,
     // The assigned device id (becomes argv[1]), or protocol.no_device.
     device_id: u64 = protocol.no_device,

test/qemu_test.py

@@ -447,7 +447,7 @@ CASES = [
                r"device-manager: child added[\s\S]*"
                r"device-manager: test mode: killing the reporter[\s\S]*"
                r"device-manager: child removed[\s\S]*"
-               r"device-manager: restarting usb-xhci-bus[\s\S]*"
+               r"device-manager: restarting \S*usb-xhci-bus[\s\S]*"
                r"device-manager: child added",
      "fail":   r"DANOS-TEST-RESULT: FAIL"},
     # USB HID end to end: boot the full tree, enumerate the xHCI, and let the

tools/make-fat-image.py

@@ -179,14 +179,17 @@ def short_name_for(name, used):
     else:
         base, ext = name, ""
     upper_base, upper_ext = base.upper(), ext.upper()
-    # A name fits 8.3 if it is short enough and uses valid characters; a lowercase
-    # name is simply stored uppercased (FAT is case-insensitive, so the bootloader
-    # and the danos driver still find it). Only genuinely non-8.3 names (too long,
-    # e.g. initial-ramdisk.img) get a mangled short name plus LFN entries.
+    # A name fits 8.3 if it is short enough and uses valid characters. The raw
+    # 8.3 entry is always uppercase; if that loses the real name's case (e.g.
+    # "init" -> "INIT"), a long-name chain carries the exact name. This matters
+    # because the EFI loader *enumerates* /system to build the ramdisk — it gets
+    # back whatever the directory stores, so the stored name must be exact, not
+    # merely case-insensitively findable.
     fits = (1 <= len(base) <= 8 and len(ext) <= 3
             and all(c in VALID_83 for c in upper_base + upper_ext))
     if fits:
-        return (upper_base.ljust(8) + upper_ext.ljust(3)).encode("ascii"), False
+        exact = base == upper_base and ext == upper_ext
+        return (upper_base.ljust(8) + upper_ext.ljust(3)).encode("ascii"), not exact
     # Mangle to STEM~N.EXT.
     stem = "".join(c for c in upper_base if c in VALID_83 and c != " ")[:6] or "FILE"
     index = 1