kernel: Phase J EnterS2Idle/ExitS2Idle AcPiVerb dispatch in kstop handle

Phase J: extend the kernel AcpiScheme's kcall to dispatch
on the new EnterS2Idle and ExitS2Idle AcPiVerb variants
from the local syscall fork. The kernel's scheme/acpi.rs
kcall handler now has a match arm for each new verb.

* EnterS2Idle (= 3): sets S2IDLE_REQUESTED + signals
  kstop handle EVENT_READ with reason=2 (s2idle wake).
  acpid calls this via kcall_wo(payload=&[], metadata=[3])
  from `kstop_enter_s2idle()` in base.

* ExitS2Idle (= 4): s2idle wake path. Calls
  s2idle_signal_wake() which clears S2IDLE_REQUESTED and
  signals kstop event. This is provided for completeness;
  the typical wake path is via mwait_loop's post-handler
  which also calls s2idle_signal_wake.

Hardware-agnostic: the new typed-AcPiVerb API works on
any platform with Modern Standby firmware (Dell, HP,
Lenovo, LG Gram, etc.). The kstop string-arg path
('s2idle' / 's3X') remains available as a fallback for
older acpid builds.

The local syscall fork (local/sources/syscall/) provides
the new AcPiVerb variants via the [patch.crates-io]
overrides in base/Cargo.toml and kernel/Cargo.toml. The
local libredox fork (local/sources/libredox/) breaks the
type-identity barrier that previously caused E0277 errors
in scheme-utils and daemon.

src/scheme/acpi.rs

@@ -256,6 +256,34 @@ impl KernelScheme for AcpiScheme {
                 // reason value.
                 Ok(*KSTOP_FLAG.lock(token.token()) as usize)
             }
+            AcpiVerb::EnterS2Idle => {
+                // Phase J: typed-AcpiVerb path. acpid calls
+                // this (via kcall_wo) instead of writing the
+                // "s2idle" string to the kstop handle. The
+                // payload is empty; the verb code is the
+                // signal. Hardware-agnostic — works on any
+                // platform with Modern Standby firmware
+                // (Dell, HP, Lenovo, LG Gram, etc.).
+                if handle != HandleBits::KSTOP_HANDLE {
+                    return Err(Error::new(EINVAL));
+                }
+                s2idle_request_set();
+                kstop_set_reason(2); // s2idle wake reason
+                Ok(0)
+            }
+            AcpiVerb::ExitS2Idle => {
+                // Phase J: s2idle wake. The kernel's mwait_loop
+                // post-handler already clears S2IDLE_REQUESTED
+                // and signals the kstop event with reason=2;
+                // this verb is provided for completeness (e.g.
+                // when acpid wants to force the wake path
+                // without going through MWAIT).
+                if handle != HandleBits::KSTOP_HANDLE {
+                    return Err(Error::new(EINVAL));
+                }
+                s2idle_signal_wake();
+                Ok(0)
+            }
         }
     }
 }