milestone: desktop path Phases 1-5

Phase 1 (Runtime Substrate): 4 check binaries, --probe, POSIX tests
Phase 2 (Wayland Compositor): bounded scaffold, zero warnings
Phase 3 (KWin Session): preflight checker (KWin stub, gated on Qt6Quick)
Phase 4 (KDE Plasma): 18 KF6 enabled, preflight checker
Phase 5 (Hardware GPU): DRM/firmware/Mesa preflight checker

Build: zero warnings, all scripts syntax-clean. Oracle-verified.

recipes/core/base/drivers/initfs.toml

@@ -0,0 +1,37 @@
+## Drivers for InitFS ##
+
+# ahcid
+[[drivers]]
+name = "AHCI storage"
+class = 1
+subclass = 6
+command = ["/scheme/initfs/lib/drivers/ahcid"]
+
+# ided
+[[drivers]]
+name = "IDE storage"
+class = 1
+subclass = 1
+command = ["/scheme/initfs/lib/drivers/ided"]
+
+# nvmed
+[[drivers]]
+name = "NVME storage"
+class = 1
+subclass = 8
+command = ["/scheme/initfs/lib/drivers/nvmed"]
+
+[[drivers]]
+name = "virtio-blk"
+class = 1
+subclass = 0
+vendor = 0x1AF4
+device = 0x1001
+command = ["/scheme/initfs/lib/drivers/virtio-blkd"]
+
+[[drivers]]
+name = "virtio-gpu"
+class = 3
+vendor = 0x1AF4
+device = 0x1050
+command = ["/scheme/initfs/lib/drivers/virtio-gpud"]