docs: record python harness migration; drop superseded policy docs

- 06-BUILD-SYSTEM-SETUP: note which QEMU proof scripts use
  qemu-login-expect.py vs host expect
- 01-REDOX-ARCHITECTURE, LOCAL-FORK-SUPREMACY-POLICY,
  SYSTEM-STABILITY-AND-UPSTREAM-SYNC-PLAN, UPSTREAM-SYNC-PROCEDURE:
  sync with current fork-model and sync-procedure state
- Delete archived/SOURCE-ARCHIVAL-POLICY.md and
  fork-push-status/2026-07-12-Round-5-phase-4.1.md — superseded by the
  current local-fork model docs and newer fork-push-status rounds
- config/redbear-mini.toml: trailing newline

docs/01-REDOX-ARCHITECTURE.md

@@ -143,6 +143,12 @@ usbhidd (USB HID), inputd (input multiplexor)
 
 ## 4. Orbital Display Server
 
+> **Note (2026-07-20):** Orbital is Redox's *reference* display server, documented here as
+> architecture background. It is **not** Red Bear's desktop direction — Red Bear targets a
+> Wayland compositor path (KWin) on top of DRM/KMS. See
+> `../local/docs/CONSOLE-TO-KDE-DESKTOP-PLAN.md` for the canonical desktop plan and
+> `../local/docs/WAYLAND-IMPLEMENTATION-PLAN.md` for the Wayland subsystem path.
+
 Orbital is Redox's display server, window manager, and compositor — all in one userspace daemon.
 
 ### Window Creation (via Scheme)

docs/06-BUILD-SYSTEM-SETUP.md

@@ -60,6 +60,13 @@ sudo apt-get install --assume-yes \
   xdg-utils xxd zip zstd qemu-system-x86 qemu-kvm
 ```
 
+> **QEMU test harnesses:** the login-based QEMU proof scripts drive the guest over its
+> serial console. Most still use the host `expect` package (listed above). The low-level
+> controller proofs (`test-ps2-qemu.sh`, `test-timer-qemu.sh`, `test-iommu-qemu.sh`,
+> `test-usb-storage-qemu.sh`) and a growing set of runtime proofs instead use
+> `local/scripts/qemu-login-expect.py`, a standard-library-only Python replacement that
+> needs no `expect` install. The system `expect` package remains required for the rest.
+
 #### Fedora
 
 ```bash