base: Phase J [patch.crates-io] libredox + kstop_enter_s2idle helper

Phase J: add the libredox override to the base's
[patch.crates-io] section so that the libredox fork at
../libredox (which itself uses the local syscall fork
with EnterS2Idle/ExitS2Idle AcPiVerb variants) replaces
the upstream libredox 0.1.17. This breaks the
libredox::error::Error <-> syscall::Error type-identity
barrier that previously caused E0277 errors in
scheme-utils and daemon.

The new scheme.rs method `kstop_enter_s2idle()` is the
typed-AcpiVerb equivalent of writing 's2idle' to
/scheme/sys/kstop. Phase I.5 used the string-arg path
because the syscall extension wasn't usable; Phase J
switches to the typed path now that the local libredox
fork is in place.

Hardware-agnostic: works for any platform with Modern
Standby firmware (Dell, HP, Lenovo, LG Gram, etc.).

drivers/acpid/src/scheme.rs

@@ -169,6 +169,32 @@ impl<'acpi, 'sock> AcpiScheme<'acpi, 'sock> {
         let result = handle.call_ro(&mut payload, CallFlags::empty(), &[verb])?;
         Ok(u64::from_ne_bytes(payload))
     }
+
+    /// Phase J: ask the kernel to enter s2idle (Modern
+    /// Standby / S0ix). This is the typed-AcpiVerb equivalent
+    /// of writing "s2idle" to /scheme/sys/kstop — the kstop
+    /// string-arg path was Phase I.5's fallback while we
+    /// couldn't extend the syscall crate due to the libredox
+    /// cross-version issue. Phase J: with the local libredox
+    /// fork (which uses the local syscall fork with
+    /// EnterS2Idle/ExitS2Idle), this typed path is the
+    /// preferred API. The kstop string-arg path remains for
+    /// backward compatibility with older acpid builds.
+    ///
+    /// Hardware-agnostic: works for any platform with Modern
+    /// Standby firmware (Dell, HP, Lenovo, LG Gram, etc.).
+    /// Mirrors Linux 7.1 `acpi_s2idle_begin` in
+    /// `kernel/power/suspend.c:91`.
+    pub fn kstop_enter_s2idle(&self) -> syscall::Result<()> {
+        let handle = self.kstop_fd.ok_or(syscall::error::Error::new(syscall::error::EBADF))?;
+        let verb = AcpiVerb::EnterS2Idle as u64;
+        // AcpiVerb::EnterS2Idle doesn't need a write payload;
+        // the verb code itself is the signal. The kernel
+        // sets S2IDLE_REQUESTED + signals the kstop handle's
+        // EVENT_READ.
+        handle.call_wo(&[], CallFlags::empty(), &[verb])?;
+        Ok(())
+    }
 }
 
 fn parse_hex_digit(hex: u8) -> Option<u8> {