CI: make the Autodesk connector workflow a test gate, ship it on macOS

Three related cleanups to how the bonsaiviewer-autodesk connector is built
and shipped.

build-bonsaiviewer-autodesk.yml no longer builds a bundle. Its four-runner
matrix produced autodesk-<os>-<arch>.zip artifacts that nothing consumed —
shipping happens in the platform pipelines, which each invoke
packaging/build.py themselves. What is left is the crate's only lint and
test coverage, so the workflow is renamed to match what it does and a
header comment records where the shipped binary actually comes from.

build_osx.yml now builds and bundles the connector, which it never did:
macOS users have been getting a Bonsai Viewer with no Autodesk connector at
all. ConnectorDiscovery resolves applicationDirPath()/connectors, which
inside a bundle is Contents/MacOS, so that is where the folder lands.

The tkinter probes in the Windows and Linux workflows are dropped. They
guarded the old PyInstaller connector's Tk GUI (de7520418) and have been
dead since the Rust rewrite (9d9f4054f); python3.11-tkinter goes with them.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

.github/workflows/build_win.yml

@@ -68,16 +68,11 @@ jobs:
         with:
           python-version: '3.12'
 
-      # The connector's PyInstaller bundle embeds a tkinter GUI; verify Tk is
-      # present so a missing-tk regression fails here, not inside the build.
-      - name: Verify tkinter is available
-        run: python -c "import tkinter; print('Tk', tkinter.TkVersion)"
-
       # Build the Autodesk connector before the C++ build: build-all-win.py
       # bundles it next to BonsaiViewer.exe while archiving the executables.
       # bonsaiviewer-autodesk is a Rust connector; packaging/build.py runs
       # `cargo build --release` and stages the binary + connector.json into
-      # dist/autodesk/ — same layout the old PyInstaller flow produced.
+      # dist/autodesk/.
       - name: Build Autodesk connector
         working-directory: src/bonsaiviewer-autodesk
         run: python packaging/build.py