fix(windows): add the Win32_System_Power feature the crate needs

config.rs reads AC line status through GetSystemPowerStatus, but the
windows crate feature list never enabled Win32_System_Power, so the
Windows target failed to compile with E0432 on that import.

The Windows build has been broken this whole time and nothing caught it:
GitHub Actions only ran on tag pushes, and the local machine is Linux.
The new CI workflow builds both targets on every push, which surfaced it
on the first run.

Verified by checking the crate's windows:: import paths against the
x86_64-pc-windows-gnu target directly.

Cargo.toml

@@ -54,5 +54,6 @@ windows = { version = "0.58.0", features = [
     "Win32_System_Threading",
     "Win32_System_LibraryLoader",
     "Win32_System_Console",
+    "Win32_System_Power",
     "Win32_UI_Shell",
 ] }