feat(clients/windows): port the Vulkan session client to Windows — session-always

The punktfunk-session Vulkan client (clients/linux-session, now clients/session)
builds and runs on Windows; the WinUI shell spawns it for every stream. Verified
live: 10-bit HEVC via Vulkan Video on both AMD (iGPU) and NVIDIA, 5120x1440 at
130 fps / 8 ms end-to-end on the RTX 4090.

- pf-ffvk: Windows bindgen branch (FFMPEG_DIR + PF_FFVK_VULKAN_INCLUDE, no
  pkg-config); provisioning fetches Vulkan-Headers (pinned v1.4.309).
- pf-client-core: builds on Windows — WASAPI audio (audio_wasapi.rs, cfg-swapped
  via #[path], same surface as the PipeWire twin), VAAPI/dmabuf gated inline
  (chain = vulkan -> software), trust reads the WinUI shell's %APPDATA% stores
  (parity tests pin both serialized shapes), Settings gains adapter/hdr_enabled
  (serde-defaulted; Linux stores unaffected).
- pf-presenter: builds on Windows — dmabuf module Linux-gated; SDL keyboard grab
  while captured (Alt+Tab/Win reach the host); pick_device ranks discrete over
  integrated (device 0 was the iGPU on hybrid boxes — the silent footgun) and
  honors PUNKTFUNK_VK_ADAPTER (the Settings GPU pick, exported by the session).
- run loop: block in one SDL wait woken by input AND decoded frames (a per-
  session forwarder pushes a FrameWake user event) instead of a 1 ms poll —
  measured 111%% -> 5%% of a core (NVIDIA), 86%% -> 3.5%% (AMD), stats unchanged.
  The pump's decode-fence wait became once-per-window sampling (no per-frame
  pipeline stall; the stat now shows true backlog).
- pf-console-ui: builds on Windows (skia-safe msvc prebuilts); font lookup falls
  through fontconfig aliases to concrete DirectWrite families (Consolas/Segoe UI)
  — browse/coverflow works, verified against a live host.
- WinUI shell: session-always via new src/spawn.rs (GTK spawn.rs port —
  CREATE_NO_WINDOW, stdout contract, kill handle); the Stream screen is a status
  card (chips + stage lines from the child's stats). The legacy in-process
  D3D11VA path stays behind Settings "Streaming engine" / PUNKTFUNK_BUILTIN_
  STREAM=1 as the A/B baseline until Phase 8 deletes it. SessionParams.video_caps
  makes the HDR toggle real.
- clients/linux-session renamed to clients/session (builds for both OSes).
- CI/MSIX: both workflows build/test both bins with widened path filters; the
  MSIX ships punktfunk-session.exe. ARM64 session builds --no-default-features
  (rust-skia has no aarch64-pc-windows-msvc prebuilts; flip when it does).

A/B on this box (5120x1440 HEVC vs home-worker-5): NVIDIA Vulkan 130 fps / 8 ms
e2e / 1.6 ms decode — clearly better than the built-in path. The AMD iGPU VCN
saturates at ~52 fps where its own D3D11VA does ~70 — Adrenalin Vulkan decode is
slower on APU silicon; discrete RDNA validation gates Phase 8.

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

crates/pf-console-ui/Cargo.toml

@@ -8,17 +8,26 @@ license.workspace = true
 authors.workspace = true
 repository.workspace = true
 
-[target.'cfg(target_os = "linux")'.dependencies]
+# Same Linux+Windows gating as the rest of the client stack.
+[target.'cfg(any(target_os = "linux", windows))'.dependencies]
 pf-presenter = { path = "../pf-presenter" }
 # MenuEvent/MenuPulse (the gamepad service's menu mode drives the library).
 pf-client-core = { path = "../pf-client-core" }
 
 # Skia on the presenter's VkDevice (`vulkan`); `textlayout` = skparagraph/harfbuzz for
 # the typography the console library needs (~15 MB stripped, prebuilt binaries exist for
-# this feature set on x86_64-unknown-linux-gnu — a source build is never triggered).
+# this feature set on x86_64-unknown-linux-gnu AND x86_64-pc-windows-msvc — a source
+# build is never triggered on either).
 skia-safe = { version = "0.87", features = ["vulkan", "textlayout"] }
 ash = { version = "0.38", features = ["loaded"] }
-sdl3 = { version = "0.18", features = ["hidapi", "ash"] }
 
 anyhow = "1"
 tracing = "0.1"
+
+# Linux links the system SDL3; Windows builds it from source (same choice as the rest
+# of the workspace's Windows SDL consumers).
+[target.'cfg(target_os = "linux")'.dependencies]
+sdl3 = { version = "0.18", features = ["hidapi", "ash"] }
+
+[target.'cfg(windows)'.dependencies]
+sdl3 = { version = "0.18", features = ["hidapi", "ash", "build-from-source"] }

crates/pf-console-ui/src/lib.rs

@@ -8,14 +8,14 @@
 //! purpose, it proves the whole shared-device pipeline. The gamepad library moves in
 //! next.
 
-#[cfg(target_os = "linux")]
+#[cfg(any(target_os = "linux", windows))]
 pub mod library;
-#[cfg(target_os = "linux")]
+#[cfg(any(target_os = "linux", windows))]
 mod library_ui;
-#[cfg(target_os = "linux")]
+#[cfg(any(target_os = "linux", windows))]
 mod skia_overlay;
 
-#[cfg(target_os = "linux")]
+#[cfg(any(target_os = "linux", windows))]
 pub use library::{LibraryGame, LibraryPhase, LibraryShared};
-#[cfg(target_os = "linux")]
+#[cfg(any(target_os = "linux", windows))]
 pub use skia_overlay::SkiaOverlay;

crates/pf-console-ui/src/library_ui.rs

@@ -655,11 +655,27 @@ impl Fonts {
     }
 }
 
+/// Resolve the first available family. Generic aliases ("sans-serif", "monospace")
+/// resolve through fontconfig on Linux; Windows' DirectWrite-backed FontMgr has no
+/// generic aliases, so the list falls through to concrete family names there.
+pub(crate) fn match_first_family(
+    mgr: &skia_safe::FontMgr,
+    families: &[&str],
+    style: FontStyle,
+) -> Option<Typeface> {
+    families
+        .iter()
+        .find_map(|f| mgr.match_family_style(f, style))
+}
+
 pub(crate) fn build_fonts() -> Result<Fonts> {
     let mgr = skia_safe::FontMgr::new();
-    let sans = mgr
-        .match_family_style("sans-serif", FontStyle::normal())
-        .ok_or_else(|| anyhow!("no sans-serif typeface via fontconfig"))?;
+    let sans = match_first_family(
+        &mgr,
+        &["sans-serif", "Segoe UI", "Arial"],
+        FontStyle::normal(),
+    )
+    .ok_or_else(|| anyhow!("no sans-serif typeface (fontconfig alias or system family)"))?;
     let mut collection = FontCollection::new();
     collection.set_default_font_manager(mgr, None);
     Ok(Fonts {

crates/pf-console-ui/src/skia_overlay.rs

@@ -146,9 +146,12 @@ impl Overlay for SkiaOverlay {
             .ok_or_else(|| anyhow!("Skia DirectContext over the shared device"))?;
         context.set_resource_cache_limit(RESOURCE_CACHE_BYTES);
 
-        let typeface = FontMgr::new()
-            .match_family_style("monospace", skia_safe::FontStyle::normal())
-            .context("no monospace typeface via fontconfig")?;
+        let typeface = crate::library_ui::match_first_family(
+            &FontMgr::new(),
+            &["monospace", "Consolas", "Cascadia Mono", "Courier New"],
+            skia_safe::FontStyle::normal(),
+        )
+        .context("no monospace typeface (fontconfig alias or system family)")?;
         self.font = Some(Font::new(typeface, 14.0));
         self.fonts = Some(build_fonts()?);