ci: keep the synthesised macOS SDK symlink out of the dependency directory

libobs now builds AND installs cleanly on macOS -- libobs.framework, its
headers, and libobsConfig/libobsTargets all land. The configure then fell over
one step later, in the template's own quarantine-clearing step:

  xattr: [Errno 13] Permission denied:
    '.../.deps/sdk/MacOSX.platform/Developer/SDKs/MacOSX26.5.sdk'

`xattr -r -d com.apple.quarantine "${dependencies_dir}"` recurses, so it
followed the SDK symlink into the read-only system SDK. The symlink moves to
the build directory, where that sweep never reaches it. The xattr call itself
also stops being fatal: clearing quarantine on downloaded dependencies is a
convenience, and it should not be able to take the whole configure down.

Separately, in the adapter: the last-frame-geometry marker is cleared whenever
the session leaves Connected, so the next stream logs its first frame again.
Verified in the headless libobs harness by switching the selected camera to a
dark slot and back -- previously the switch back was silent because the
resolution had not changed, so the log stopped answering "did video come
back". It now reads:

  connected to ws://... watching cam-test
  video frame 640x360 I420
  --- switching camera to 'other-cam'
  connected to ws://... watching other-cam
  --- switching camera back to 'cam-test'
  connected to ws://... watching cam-test
  video frame 640x360 I420
  status after switch-back: connected

which also confirms the whole change-settings path: each switch mints a fresh
obs:<room>:<nonce> identity and reconnects, with no crash and no stale frame.

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

obs-adapter/src/plugin-main.cpp

@@ -377,8 +377,13 @@ void *sourceCreate(obs_data_t *settings, obs_source_t *source)
         // A camera that stopped publishing must not leave its last frame on
         // screen -- that is precisely the stale-media failure this plugin
         // exists to avoid. A null frame clears the source.
-        if (state != SessionState::Connected)
+        if (state != SessionState::Connected) {
             obs_source_output_video(self->source, nullptr);
+            // Forget the last geometry so the next stream logs its first
+            // frame again; otherwise a reconnect at the same resolution is
+            // silent, and the log stops answering "did video come back".
+            self->last_geometry.store(0);
+        }
     });
 
     {