fix(packaging): vulkan-headers build dep + ship punktfunk-session across desktop packages

The re-architecture split the Linux client into two binaries (shell + Vulkan
session streamer) and added the pf-ffvk crate, whose build.rs runs bindgen over
FFmpeg's libavutil/hwcontext_vulkan.h (#include <vulkan/vulkan.h>). Two release
regressions fell out of that on the desktop-package legs:

1. Missing build dep. The Arch build (archlinux:base-devel + its own pacman list)
   fatal-errored at `vulkan/vulkan.h file not found`. Add the Vulkan dev headers
   wherever the client compiles from a self-managed dep set: arch (PKGBUILD
   makedepends + arch.yml), rpm (spec BuildRequires + rpm.yml + fedora image),
   deb.yml (belt-and-suspenders; the rust-ci image already bakes libvulkan-dev),
   and the screenshots job. The flatpak builds offline against the GNOME SDK, so
   install Vulkan-Headers into /app as a pinned module and point pf-ffvk's bindgen
   at it via PF_FFVK_VULKAN_INCLUDE.

2. Only the shell shipped. arch/deb/rpm built and installed just punktfunk-client;
   the shell execs its sibling punktfunk-session for a connect, so desktop
   streaming would break exactly as Decky's did. Build and install BOTH binaries
   in all three, and declare the runtime Vulkan loader the session binary dlopens
   (vulkan-icd-loader / vulkan-loader / libvulkan1 — not a DT_NEEDED, so
   shlibdeps/auto-requires can't see it).

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

.gitea/workflows/arch.yml

@@ -42,7 +42,7 @@ jobs:
       - name: Install build + runtime-dev deps
         run: |
           pacman -Syu --noconfirm --needed \
-            git nodejs rust clang cmake nasm pkgconf python \
+            git nodejs rust clang cmake nasm pkgconf python vulkan-headers \
             gtk4 libadwaita sdl3 ffmpeg pipewire wayland libxkbcommon opus libei \
             mesa libglvnd unzip libarchive
           # bun builds the punktfunk-web console AND is vendored as its runtime (PF_WITH_WEB=1);

.gitea/workflows/deb.yml

@@ -60,8 +60,10 @@ jobs:
         run: |
           apt-get update
           # python3 is used by scripts/ci/gitea-release.sh for the stable-tag release attach.
+          # libvulkan-dev: /usr/include/vulkan/vulkan.h for the client's pf-ffvk bindgen
+          # (FFmpeg's hwcontext_vulkan.h includes it).
           apt-get install -y --no-install-recommends dpkg-dev python3 \
-            libgtk-4-dev libadwaita-1-dev libsdl3-dev
+            libgtk-4-dev libadwaita-1-dev libsdl3-dev libvulkan-dev
 
       # Share ci.yml's cache keys so the release build reuses its registry + target artifacts.
       - name: Cache keys
@@ -86,7 +88,10 @@ jobs:
           PUNKTFUNK_BUILD_VERSION: ${{ env.VERSION }}   # stamped into the binary (build.rs)
         run: |
           git config --global --add safe.directory "$PWD"
-          cargo build --release -p punktfunk-host -p punktfunk-client-linux --locked
+          # punktfunk-client-session is the Vulkan/Skia streamer the shell execs for a connect —
+          # both client binaries must ship (build-client-deb.sh installs both).
+          cargo build --release --locked \
+            -p punktfunk-host -p punktfunk-client-linux -p punktfunk-client-session
 
       - name: Build + smoke-boot web console (bun preset)
         # Gate the .deb on a real bun boot: the punktfunk-web .deb runs the Nitro `bun` preset

.gitea/workflows/linux-client-screenshots.yml

@@ -30,7 +30,7 @@ jobs:
         run: |
           apt-get update
           apt-get install -y --no-install-recommends \
-            libgtk-4-dev libadwaita-1-dev libsdl3-dev \
+            libgtk-4-dev libadwaita-1-dev libsdl3-dev libvulkan-dev \
             xvfb x11-utils imagemagick scrot \
             libgl1-mesa-dri mesa-vulkan-drivers \
             adwaita-icon-theme fonts-cantarell fonts-dejavu-core

.gitea/workflows/rpm.yml

@@ -54,7 +54,9 @@ jobs:
       - name: Prep
         run: |
           git config --global --add safe.directory "$PWD"
-          dnf -y install gtk4-devel libadwaita-devel SDL3-devel
+          # vulkan-headers: the client's pf-ffvk crate runs bindgen over FFmpeg's
+          # libavutil/hwcontext_vulkan.h (#include <vulkan/vulkan.h>).
+          dnf -y install gtk4-devel libadwaita-devel SDL3-devel vulkan-headers
           # sysext build (packaging/bazzite/build-sysext.sh): squashfs + SELinux labeling.
           dnf -y install squashfs-tools cpio libselinux-utils selinux-policy-targeted
           # bun builds the punktfunk-web console (--with web). Baked into the image; install it