feat(kernel): WatchDeath + SetTimer events as notification signals; adapter wakes at earliest deadline

crates/kernel/src/syscall/mod.rs

@@ -102,6 +102,20 @@ impl<P: Platform> Kernel<P> {
                 self.region_address_cap(pid, region)
                     .map(|pa| SyscallResult::Value(pa.raw())),
             ),
+            Syscall::WatchDeath {
+                process,
+                notification,
+            } => complete(
+                self.watch_death(pid, process, notification)
+                    .map(|()| SyscallResult::Ok),
+            ),
+            Syscall::SetTimer {
+                notification,
+                deadline,
+            } => complete(
+                self.set_timer(pid, notification, deadline)
+                    .map(|()| SyscallResult::Ok),
+            ),
             Syscall::Delegate {
                 slot,
                 to_endpoint,