libva-v4l2-request-fourier-debian: switch to debian-aarch64-bohr runner

Per @marfrit on PR #44 review: a native Debian trixie aarch64 runner
(debian-aarch64-bohr) is available — use it instead of the sysroot
hack from the previous commit.

The sysroot approach worked but was a workaround for not having the
right runner.  Native trixie runner is much cleaner:

  - libva-dev installs via apt-get directly from trixie's archive
    (2.22.0-3) — pkg-config returns trixie headers, driver compiles
    in __vaDriverInit_1_22 naturally.
  - No need to symlink libva.so.2 -> libva.so or rewrite .pc prefixes.
  - No bsdtar/ar/dpkg-deb juggling on an Arch runner that doesn't
    natively have dpkg.

Changes from PR v1:

  - .gitea/workflows/build.yml: libva-v4l2-request-fourier-debian
    runs-on: debian-aarch64-bohr (was arch-aarch64).  Build-deps
    installed via apt-get instead of pacman -Syu.

  - build-deb.sh: drop the sysroot download / pkgconfig rewrite /
    symlink block.  Keep the post-build ABI sanity check (nm -D |
    grep __vaDriverInit_1_22) — same defensive role as before, with
    an updated error message that points to the expected runner.

  - debian/.../changelog: -2 entry rewritten to describe the runner
    move instead of the sysroot.

Tested approach on boltzmann (aarch64): meson build against trixie
sysroot produces __vaDriverInit_1_22 (proves the source compiles
correctly with VA-API 1.22 headers).  Native runner build will
follow the same path, just without the explicit sysroot setup.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

.gitea/workflows/build.yml

@@ -971,7 +971,12 @@ jobs:
   # -------------------------------------------------------------------------
   libva-v4l2-request-fourier-debian:
     needs: libva-v4l2-request-fourier-aarch64
-    runs-on: arch-aarch64
+    # Native Debian trixie runner — the driver bakes __vaDriverInit_1_<MINOR>
+    # at compile time from <va/va.h>.  Building on Arch (libva 2.23) produced
+    # __vaDriverInit_1_23, which trixie's libva 2.22 runtime cannot bind: the
+    # .deb installed but vaInitialize() returned -1 on every host.  A native
+    # trixie runner avoids the cross-distro ABI skew entirely.
+    runs-on: debian-aarch64-bohr
     continue-on-error: true
     steps:
       - uses: actions/checkout@v4
@@ -989,9 +994,12 @@ jobs:
         run: |
           set -e
           retry() { for i in 1 2 3; do "$@" && return 0; rc=$?; echo "retry $i (exit=$rc)" >&2; sleep $((i*5)); done; return 1; }
-          retry pacman -Syu --noconfirm --needed \
-            dpkg openssh rsync curl base-devel git meson ninja pkgconf \
-            libva libdrm systemd-libs
+          export DEBIAN_FRONTEND=noninteractive
+          retry apt-get update -qq
+          retry apt-get install -y --no-install-recommends \
+              build-essential meson ninja-build pkg-config \
+              libva-dev libdrm-dev \
+              curl openssh-client rsync ca-certificates git dpkg-dev
 
       - name: install hertz deploy ssh key
         if: steps.skip-check.outputs.skip != '1'