ci: fix the three failures the first real three-platform run exposed

Linux, glibc. The LiveKit SDK's "linux-x64" asset is not actually generic:
it is built on Ubuntu 24.04 and needs GLIBC_2.38 and GLIBCXX_3.4.32, so
linking it on a 22.04 runner fails outright ("undefined reference to
std::ios_base_library_init()@GLIBCXX_3.4.32", "__isoc23_strtol@GLIBC_2.38").
That is exactly what happened when this repo's CI landed on the 22.04 Linux
runner instead of the 24.04 one. LiveKitSDK.cmake now defaults Linux to the
ubuntu-22.04 asset, which needs at most GLIBC_2.35 / GLIBCXX_3.4.30 (checked
with objdump against both archives) and therefore links and runs on 22.04 and
on everything newer -- the right floor for a plugin handed to directors as a
binary.

Linux, libobs version. The Linux job is pinned to ubuntu-24.04 rather than
ubuntu-latest, which this instance's two Linux runners answer with different
releases. 24.04's libobs-dev is 30.0.2 -- exactly the OBS version
buildspec.json pins for macOS/Windows -- so all three platforms build against
the same libobs. A 22.04 runner would have given OBS 27, a different API
surface.

macOS, no Xcode. The OBS sub-build failed its configure with "No
CMAKE_C_COMPILER could be found": the template hardcodes the Xcode generator,
and the `home-mac` runner has the Command Line Tools but no xcodebuild. The
sub-build now uses Ninja (with an explicit CMAKE_BUILD_TYPE, since Ninja is
single-config) and builds a single architecture rather than upstream's forced
universal -- this plugin is single-arch anyway, because client-sdk-cpp ships
single-arch dylibs, so a universal libobs would double the slowest step in CI
for a slice nothing links against.

While in there, generator flags are built as proper CMake lists so each
becomes its own argv entry. Upstream packs several into one space-separated
string and passes it unquoted, which execute_process hands to cmake as a
single argument; it happens not to matter for the optional flags upstream
passes, but it would silently swallow -DCMAKE_BUILD_TYPE.

Also lowers the libobs API floor in the adapter: video_format_get_parameters
instead of video_format_get_parameters_for_format. The _for_format variant
only exists from libobs 30 onwards and only differs for the 10-bit formats
(I010/P010) this source never receives, so using the older entry point keeps
the module loadable on an older OBS -- the direction that matters, since OBS
refuses modules built against a NEWER libobs than the one running.

Re-verified locally on Ubuntu 24.04 with the ubuntu-22.04 SDK asset:
ctest 6/6; the real-LiveKit integration test still reports "36 video frames,
323 audio frames, 10 state changes / 32 checks passed"; and the headless
libobs harness still logs "connected to ws://127.0.0.1:7880 ... watching
cam-test" followed by "video frame 640x360 I420" with the camera dropdown
populated from the live slot list.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RL8abRmgFXkVASHkkqiJbE

.gitea/workflows/build.yml

@@ -16,8 +16,13 @@ on:
 
 jobs:
   linux:
-    name: Linux (ubuntu-latest)
-    runs-on: ubuntu-latest
+    name: Linux (ubuntu-24.04)
+    # Pinned to 24.04 rather than ubuntu-latest, which this instance's two
+    # Linux runners answer with different releases. 24.04's libobs-dev is
+    # 30.0.2, exactly the OBS version buildspec.json pins for macOS/Windows,
+    # so all three platforms build against the same libobs. On a 22.04 runner
+    # libobs-dev is OBS 27, which is a different API surface entirely.
+    runs-on: ubuntu-24.04
     steps:
       - name: Checkout
         uses: actions/checkout@v4