fix(vdisplay/windows): Windows clippy — per-block SAFETY comments + then_some

The branch's Windows-host code never ran through the fleet Windows clippy (kept off CI); the merge
to main exposed it. Fix the 4 -D warnings failures in cfg(windows) code:
- manager.rs: 3 unsafe blocks (isolate_displays_ccd / force_extend_topology / set_virtual_primary_ccd)
  had one "both arms" SAFETY comment on the `match` line — clippy::undocumented_unsafe_blocks wants it
  immediately before each block. Split into per-block SAFETY comments.
- win_display.rs: `.then(|| …)` on a POD u32 union read → `.then_some(…)` (eager is fine, discarded
  when false) for clippy::unnecessary_lazy_evaluations.

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

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

@@ -655,10 +655,10 @@ impl VirtualDisplayManager {
                 // MODE_CHANGE storm). Opt out (extend) with PUNKTFUNK_NO_ISOLATE=1 / the console policy.
                 use crate::vdisplay::policy::Topology;
                 match topology_action() {
-                    // SAFETY (both arms): the CCD helper is `unsafe` for its topology FFI; it takes a
-                    // `Copy` `u32` by value and returns an owned `SavedConfig` (no borrowed memory crosses),
-                    // and runs under the `state` lock, the sole mutator of the topology.
                     Topology::Exclusive => {
+                        // SAFETY: `isolate_displays_ccd` is `unsafe` for its CCD topology FFI; it takes the
+                        // `Copy` target id by value and returns an owned `SavedConfig` (no borrowed memory
+                        // crosses), under the `state` lock — the sole topology mutator.
                         ccd_saved = unsafe { isolate_displays_ccd(added.target_id) };
                     }
                     Topology::Primary => {
@@ -668,8 +668,12 @@ impl VirtualDisplayManager {
                         // alongside the virtual, THEN reposition to make the virtual primary — so the
                         // physical stays active. (The bring-up above only force-EXTENDs when the
                         // virtual FAILS to auto-resolve; here it resolved, so we do it explicitly.)
+                        // SAFETY: `force_extend_topology` drives the CCD topology FFI (no args, no borrowed
+                        // memory), under the `state` lock — the sole topology mutator.
                         unsafe { force_extend_topology() };
                         thread::sleep(Duration::from_millis(300));
+                        // SAFETY: `set_virtual_primary_ccd` takes the `Copy` target id by value and returns
+                        // an owned `SavedConfig` (no borrowed memory crosses), under the `state` lock.
                         ccd_saved = unsafe { set_virtual_primary_ccd(added.target_id) };
                     }
                     Topology::Extend | Topology::Auto => {

crates/punktfunk-host/src/windows/win_display.rs

@@ -492,8 +492,10 @@ pub(crate) unsafe fn set_virtual_primary_ccd(keep_target_id: u32) -> Option<Save
         }
         let idx = p.sourceInfo.Anonymous.modeInfoIdx as usize;
         let m = modes.get(idx)?;
+        // `then_some` (eager): `sourceMode.width` is a POD `u32` union read, discarded when the arm is
+        // false — no lazy guard needed. (`then(|| …)` here trips clippy::unnecessary_lazy_evaluations.)
         (m.infoType == DISPLAYCONFIG_MODE_INFO_TYPE_SOURCE)
-            .then(|| m.Anonymous.sourceMode.width as i32)
+            .then_some(m.Anonymous.sourceMode.width as i32)
     })?;
     let others = paths.len().saturating_sub(1);