feat(clients/windows): all-vendor video pipeline rewrite + app icon + hosts-page tiles

Decode+present rewrite (first real pixels on glass for this client):

- Decode: FFmpeg D3D11VA on NVIDIA/AMD/Intel. get_format now only returns
  AV_PIX_FMT_D3D11 and lets libavcodec build the decode pool from
  hw_device_ctx (hand-built frames contexts failed three different ways:
  NVIDIA rejects DECODER|SHADER_RESOURCE arrays, BindFlags=0 fails texture
  creation, Intel rejects non-128-aligned HEVC surfaces at the first
  SubmitDecoderBuffers). A DXVA profile probe before the hwdevice commits
  hardware-vs-software up front instead of burning the opening IDR;
  extra_hw_frames covers the frames the client holds.
- Present: the decoded slice is copied with ONE display-size-boxed
  CopySubresourceRegion (a planar slice is a single subresource in D3D11;
  the old two-copy D3D12-style code silently no-opped - the black screen)
  into a sampleable NV12/P010 texture, per-plane SRVs + YUV->RGB shaders.
- New dedicated render thread (render.rs): presenting is decoupled from the
  XAML thread; frame-latency-waitable swapchain + SetMaximumFrameLatency(1),
  newest-wins drain after the wait, crossbeam frame channel with pts for a
  capture->presented p50 log.
- HiDPI: pixel-sized buffers + SetMatrixTransform(96/dpi) - was blurry at
  125/150 % scaling.
- Software fallback now feeds the same shaders (swscale -> NV12/P010 planes
  -> two dynamic plane textures); ps_rgba/X2BGR10 path deleted, hw/sw colour
  math identical.
- Adapter selection for hybrid boxes: PUNKTFUNK_ADAPTER > the window's
  monitor's adapter > default; PUNKTFUNK_D3D_DEBUG=1 debug layer.
- Session pump: request_keyframe at start and on hw->sw demotion (infinite
  GOP would otherwise sit on a black screen).

Validated live on the Arc Pro + RTX 3500 Ada laptop against the local
Windows host: 60 fps D3D11VA on both vendors, software path, GUI on glass.

Also: embedded app icon (build.rs winresource + WM_SETICON, MSIX
Square44x44 targetsize assets, pack-msix stages them) and the hosts-page
tile rework (tap-to-connect tiles with sibling overflow menu - fixes
forget-also-connects - in-tile rename editor, add-host modal via root state).

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

clients/windows/packaging/pack-msix.ps1

@@ -106,6 +106,25 @@ Copy-Item (Join-Path $assets '*') (Join-Path $layout 'Assets') -Force
 $manifest = (Get-Content -Raw $manifestTemplate).Replace('{VERSION}', $Version).Replace('{PUBLISHER}', $Publisher).Replace('{ARCH}', $Arch)
 Set-Content -Path (Join-Path $layout 'AppxManifest.xml') -Value $manifest -Encoding UTF8
 
+# --- resource index (resources.pri) ---
+# The shell resolves the manifest's logo assets through MRT, so the qualified variants
+# (Square44x44Logo.targetsize-*_altform-unplated.png — the alpha-transparent taskbar icons) only
+# take effect if a pri indexes them; without one the taskbar falls back to plating the base
+# 44x44 onto a solid square (the white-cornered icon). makepri's default config indexes the
+# layout's asset files AND merges any existing .pri it finds (reactor's staged WinUI resources)
+# via its PRI indexer, yielding one combined resources.pri. Output lands outside the layout
+# first — the reactor pri is an input while indexing — then replaces it.
+$makepri = Find-SdkTool 'makepri.exe'
+$priconfig = Join-Path $OutDir 'priconfig.xml'
+New-Item -ItemType Directory -Force -Path $OutDir | Out-Null
+& $makepri createconfig /cf $priconfig /dq en-US /o
+if ($LASTEXITCODE -ne 0) { throw "makepri createconfig failed ($LASTEXITCODE)" }
+$priOut = Join-Path $OutDir 'resources.pri'
+if (Test-Path $priOut) { Remove-Item $priOut -Force }
+& $makepri new /pr $layout /cf $priconfig /mn (Join-Path $layout 'AppxManifest.xml') /of $priOut /o
+if ($LASTEXITCODE -ne 0) { throw "makepri new failed ($LASTEXITCODE)" }
+Move-Item $priOut (Join-Path $layout 'resources.pri') -Force
+
 Write-Host "layout assembled at $layout :"
 Get-ChildItem $layout -Recurse -File | ForEach-Object { "  $($_.FullName.Substring($layout.Length + 1))" }