feat(client/windows): PyroWave decode + surface it in the GUI codec picker

The decoder was gated to Linux because, when it landed, the Windows client
still had its own in-process WinUI/D3D11 presenter and the PyroWave present
path there was an open question. That client has since been retired: Windows
now spawns the SAME Vulkan session presenter as Linux, and the decoder is
plain Vulkan compute on the presenter's device (no fds, no dmabuf, no D3D11
interop), so the question that gated it answered itself. pyrowave-sys already
builds on Windows too -- the Windows HOST encoder ships on it.

So this is a port by un-gating: every cfg(all(target_os = "linux", feature =
"pyrowave")) becomes any(linux, windows) -- decoder module, backend variant,
Decoder::new_pyrowave, the CODEC_PYROWAVE advertisement, the session pump's
opt-in/build/label arms, and the presenter's planar CSC pass. No new code.

Then offer it in the Windows GUI, which is what prompted this. It stays
preference-only (resolve_codec never auto-picks it) and a host or device that
can't do PyroWave just falls back down the ladder to HEVC.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

crates/pf-client-core/src/session.rs

@@ -227,7 +227,7 @@ fn pump(
     // the plan-§3 contract: the host only ever picks PyroWave when the client names it.
     #[allow(unused_mut)]
     let mut preferred = params.preferred_codec;
-    #[cfg(all(target_os = "linux", feature = "pyrowave"))]
+    #[cfg(all(any(target_os = "linux", windows), feature = "pyrowave"))]
     if std::env::var("PUNKTFUNK_PREFER_PYROWAVE").as_deref() == Ok("1") {
         if params.vulkan.as_ref().is_some_and(|v| v.pyrowave_decode) {
             preferred = punktfunk_core::quic::CODEC_PYROWAVE;
@@ -296,7 +296,7 @@ fn pump(
     // A negotiated PyroWave session decodes on the presenter's device, no FFmpeg —
     // reachable only through the explicit preference above (resolve_codec never
     // auto-picks the bit), so failing loudly here is failing an opted-in experiment.
-    #[cfg(all(target_os = "linux", feature = "pyrowave"))]
+    #[cfg(all(any(target_os = "linux", windows), feature = "pyrowave"))]
     let built = if connector.codec == punktfunk_core::quic::CODEC_PYROWAVE {
         let mode = connector.mode();
         // The wavelet bitstream has no VUI: the negotiated Welcome colour signalling IS
@@ -325,7 +325,7 @@ fn pump(
     } else {
         Decoder::new(codec_id, &params.decoder, params.vulkan.as_ref())
     };
-    #[cfg(not(all(target_os = "linux", feature = "pyrowave")))]
+    #[cfg(not(all(any(target_os = "linux", windows), feature = "pyrowave")))]
     let built = Decoder::new(codec_id, &params.decoder, params.vulkan.as_ref());
     let mut decoder = match built {
         Ok(d) => d,
@@ -528,7 +528,7 @@ fn pump(
                             DecodedImage::VkFrame(_) => "vulkan",
                             #[cfg(windows)]
                             DecodedImage::D3d11(_) => "d3d11va",
-                            #[cfg(all(target_os = "linux", feature = "pyrowave"))]
+                            #[cfg(all(any(target_os = "linux", windows), feature = "pyrowave"))]
                             DecodedImage::PyroWave(_) => "pyrowave",
                         };
                         if total_frames == 1 {
@@ -539,7 +539,10 @@ fn pump(
                                 DecodedImage::VkFrame(v) => (v.width, v.height, "vulkan-video"),
                                 #[cfg(windows)]
                                 DecodedImage::D3d11(d) => (d.width, d.height, "d3d11va"),
-                                #[cfg(all(target_os = "linux", feature = "pyrowave"))]
+                                #[cfg(all(
+                                    any(target_os = "linux", windows),
+                                    feature = "pyrowave"
+                                ))]
                                 DecodedImage::PyroWave(f) => (f.width, f.height, "pyrowave"),
                             };
                             tracing::info!(width = w, height = h, path, "first frame decoded");