absorb: 41 orphaned base patches re-applied (Phase 1.0A)

Per local/docs/PATCH-PRESERVATION-AUDIT-2026-07-12.md the base
fork was carrying only 38 of 100 patches in local/patches/base/.
The other 62 patches' content was silently missing from the fork
working tree, even though their .patch files were preserved.

This commit re-applies 41 patches that genuinely still apply
cleanly + 17 hunks that partially applied. Recovery covers:

- D-Bus initfs service wiring (P4-initfs-dbus-services)
- USB service wiring (P4-initfs-usb-drm-services)
- netcfg/dhcp/dhcpv6 driver fixes
- acpid shutdown/PM/quirk fixes
- inputd/ps2d hard-fail logging
- pcid driver interface refinements (server cmd channel)
- virtio-core for VirtualBox support
- ixgbed/rtl8139/rtl8168 net drivers
- ahcid NCQ + per-function interrupt coalescing
- logd persistent logging
- bootstrap procmgr race-condition fixes
- cargo version pin to +rb0.3.0 (synchronized release branch)

58 files changed, +1444/-318 lines.

Untracked mnt/ tree and *.orig / *.rej files cleaned up after
patch application (leftover from absolute-path patch headers).

drivers/virtio-core/src/spec/split_virtqueue.rs

@@ -197,9 +197,9 @@ impl ChainBuilder {
     }
 
     pub fn build(mut self) -> Vec<Buffer> {
-        let last_buffer = self.buffers.last_mut().expect("virtio-core: empty chain");
-        last_buffer.flags.remove(DescriptorFlags::NEXT);
-
+        if let Some(last_buffer) = self.buffers.last_mut() {
+            last_buffer.flags.remove(DescriptorFlags::NEXT);
+        }
         self.buffers
     }
 }