feat: GPUI desktop port foundation

- scene crate: full project/scene/element model, serde round-trip
  proven against the web SerializedProject shape
- transfer crate: .ocp zip container, cross-compat with web fflate
  archives proven in both directions
- storage crate: filesystem project store replacing IndexedDB,
  .ocp import/export
- media crate: ffmpeg-next 8 decoder (frames, audio, thumbnails,
  waveform summaries)
- playback crate: wall-clock anchored, frame-rounded playback clock
- gpu crate: native texture readback; compositor renders headless
  offscreen on Vulkan (spike test)
- flake devshell: rust toolchain, GPUI native deps, ffmpeg dev,
  bindgen clang args; GPUI hello-world builds
- port plan in notes/gpui-port.md

1 files changed, 41 insertions, 0 deletions

diff --git a/flake.nix b/flake.nix
index fab10705..8edaccbc 100644
--- a/flake.nix
+++ b/flake.nix
@@ -25,7 +25,48 @@
               bun
               just
               nodejs
+
+              cargo
+              clippy
+              rustc
+              rustfmt
+
+              cmake
+              pkg-config
+
+              alsa-lib
+              fontconfig
+              freetype
+              libxkbcommon
+              openssl
+              vulkan-loader
+              wayland
+              libX11
+              libxcb
+
+              ffmpeg-headless.dev
+              llvmPackages.libclang
             ];
+
+            env.LIBCLANG_PATH = "${pkgs.llvmPackages.libclang.lib}/lib";
+
+            shellHook = ''
+              export BINDGEN_EXTRA_CLANG_ARGS="$(cat ${pkgs.stdenv.cc}/nix-support/cc-cflags 2>/dev/null) $(cat ${pkgs.stdenv.cc}/nix-support/libc-cflags 2>/dev/null) $BINDGEN_EXTRA_CLANG_ARGS"
+              export LD_LIBRARY_PATH=${
+                pkgs.lib.makeLibraryPath (
+                  with pkgs; [
+                    alsa-lib
+                    fontconfig
+                    freetype
+                    libxkbcommon
+                    vulkan-loader
+                    wayland
+                    libX11
+                    libxcb
+                  ]
+                )
+              }:$LD_LIBRARY_PATH
+            '';
           };
         }
       );