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/zerod/src/main.rs

@@ -0,0 +1,35 @@
+use redox_scheme::Socket;
+
+use scheme::ZeroScheme;
+use scheme_utils::Blocking;
+
+mod scheme;
+
+enum Ty {
+    Null,
+    Zero,
+}
+
+fn main() {
+    daemon::SchemeDaemon::new(daemon);
+}
+
+fn daemon(daemon: daemon::SchemeDaemon) -> ! {
+    let ty = match &*std::env::args().nth(1).unwrap() {
+        "null" => Ty::Null,
+        "zero" => Ty::Zero,
+        _ => panic!("needs to be called with either null or zero as argument"),
+    };
+
+    let socket = Socket::create().expect("zerod: failed to create zero scheme");
+    let mut zero_scheme = ZeroScheme(ty);
+    let zero_handler = Blocking::new(&socket, 16);
+
+    let _ = daemon.ready_sync_scheme(&socket, &mut zero_scheme);
+
+    libredox::call::setrens(0, 0).expect("zerod: failed to enter null namespace");
+
+    zero_handler
+        .process_requests_blocking(zero_scheme)
+        .expect("zerod: failed to process events from zero scheme");
+}