fix(windows): clippy/build cleanups the on-glass build surfaced (-D warnings)

Built the host crate (`cargo clippy --features nvenc -D warnings`) and the driver
workspace (`cargo build`) on the RTX box — the project's intended Windows gate,
which `cargo check` (what the goal1/§2.5 work used) never runs. It surfaced lint
issues accumulated across the goal1 / §2.5 / this-session Windows work:

- 9× redundant `as *mut c_void` after `.as_raw_handle()` (already `*mut c_void`):
  idd_push.rs (3, this session), service.rs (3, this session), manager.rs (3,
  pre-existing §2.5 — my OwnedHandle work copied the idiom). Removed the casts +
  the now-unused `use std::ffi::c_void` in idd_push.rs / manager.rs (service still
  uses it).
- `if_same_then_else` in session_plan.rs::resolve_topology (pre-existing goal1
  stage 3): collapsed the two `false` arms into one condition (behavior identical).
- `unused_unsafe` in the driver `pod_init!` macro: it expands at call sites already
  inside an `unsafe` block, where its own `unsafe` is redundant — `#[allow(
  unused_unsafe)]` (needed at the non-unsafe sites, redundant at the nested ones).

After these, BOTH builds are clean on the box — validating the whole session's
blind Windows + driver work compiles + passes clippy on real hardware.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

crates/punktfunk-host/src/vdisplay/windows/manager.rs

@@ -13,7 +13,6 @@
 //! its `Drop` releases the refcount (a *stale* lease — its monitor was preempted + recreated under it —
 //! is a no-op, so it can never tear down the live monitor).
 
-use std::ffi::c_void;
 use std::os::windows::io::{AsRawHandle, OwnedHandle};
 use std::sync::atomic::{AtomicBool, AtomicU32, AtomicU64, Ordering};
 use std::sync::{Arc, Mutex, Once, OnceLock};
@@ -160,11 +159,11 @@ impl VirtualDisplayManager {
     /// double-open.
     fn ensure_device(&self) -> Result<HANDLE> {
         if let Some(d) = self.device.get() {
-            return Ok(HANDLE(d.as_raw_handle() as *mut c_void));
+            return Ok(HANDLE(d.as_raw_handle()));
         }
         let (handle, watchdog_s) = unsafe { self.driver.open()? };
         self.watchdog_s.store(watchdog_s, Ordering::Relaxed);
-        let raw = HANDLE(handle.as_raw_handle() as *mut c_void);
+        let raw = HANDLE(handle.as_raw_handle());
         let _ = self.device.set(Arc::new(handle));
         Ok(raw)
     }
@@ -174,7 +173,7 @@ impl VirtualDisplayManager {
     fn device_handle(&self) -> Option<HANDLE> {
         self.device
             .get()
-            .map(|d| HANDLE(d.as_raw_handle() as *mut c_void))
+            .map(|d| HANDLE(d.as_raw_handle()))
     }
 
     /// Open + initialise the backend (validates the driver is present). Mirrors the old