build: the unix paths retire — configuration, logs, and volumes move into the danos tree

/etc/init.csv and /etc/devices.csv become /system/configuration/*.csv (the
repo's etc/ moves to system/configuration/, mirroring the runtime tree),
/var/log becomes /system/logs, and /mnt/usb becomes /volumes/usb. The
kernel VFS gains a carve-out so FAT may serve exactly /system/configuration
and /system/logs beneath the initrd-backed /system while /system and /test
themselves stay unshadowable; FAT's single /var mount splits into those two
rewritten mounts. The kvfs readdir check learns /system's third child and
the ramdisk spawn sweep skips the configuration tree.

Suite 106/106.

system/configuration/init-diagnose.csv

@@ -0,0 +1,13 @@
+# /system/configuration/init.csv — diagnose variant (-Ddiagnose), bundled at
+# /system/configuration/init.csv.
+#
+# The display stack (display, display-demo) is omitted so the kernel's timestamped
+# on-screen boot transcript is never suppressed — the bring-up timeline (USB,
+# storage, logger) stays readable on real hardware with no serial. See
+# system/configuration/init.csv for the format; this file must otherwise track it.
+#
+# service                          args...
+/system/services/input
+/system/services/device-manager
+/system/services/fat
+/system/services/logger