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/session_plan.rs

@@ -138,9 +138,7 @@ fn resolve_topology() -> SessionTopology {
     let cfg = crate::config::config();
     // `NO_HELPER`/`NO_WGC` force single-process; IDD-push captures in-process in Session 0 (no helper);
     // otherwise the helper runs when forced or when we're SYSTEM (in-process WGC can't activate there).
-    let helper = if cfg.no_helper || crate::capture::wgc_disabled() {
-        false
-    } else if cfg.idd_push {
+    let helper = if cfg.no_helper || crate::capture::wgc_disabled() || cfg.idd_push {
         false
     } else {
         cfg.force_helper || crate::capture::wgc_relay::running_as_system()