Add CI workflow

Mirrors the MultibodyComponents CI: self-hosted runner, private JuliaHub
registries, and the test suite run under a virtual display. Includes a
temporary step that takes MultibodyComponents from its main branch, since
the models require the BodyShape center-of-mass fix
(JuliaComputing/MultibodyComponents.jl#150) which is not yet in any
registered release; remove the step and bump the compat bound once a fixed
release is registered.

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

Author: baggepinnen

.github/workflows/CI.yml

@@ -0,0 +1,63 @@
+name: CI
+
+on:
+  push:
+    branches:
+      - main
+    tags:
+      - "*"
+  pull_request:
+
+env:
+  JULIA_PKG_SERVER: internal.juliahub.com
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  test:
+    name: Julia ${{ matrix.version }} - ${{ matrix.os }} - ${{ matrix.arch }} - ${{ github.event_name }}
+
+    runs-on: self-hosted
+
+    strategy:
+      fail-fast: false
+      matrix:
+        version:
+          - "1.12"
+        os:
+          - self-hosted
+        arch:
+          - x64
+
+    steps:
+      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
+
+      - uses: julia-actions/setup-julia@4c0cb0fce8556fdb04a90347310e5db8b1f98fb9 # v2.7.0
+        with:
+          version: ${{ matrix.version }}
+          arch: ${{ matrix.arch }}
+
+      - name: "Set up private JuliaHub registries"
+        uses: "JuliaComputing/set-up-private-juliahub-registries@2f465506027adbe8086afc41dd3514e9020d1577" # v2.0.0
+        with:
+          encoded-juliahub-token: "${{ secrets.JULIAHUB_TOKEN_ENCODED }}"
+          ssh-key: "${{ secrets.JULIASIM_REGISTRY_SSH_KEY }}"
+          enable-JSMLComponents: "true"
+          enable-JuliaHubRegistry: "true"
+
+      # TEMPORARY: the 3D models require the BodyShape center-of-mass fix
+      # (JuliaComputing/MultibodyComponents.jl#150), which is not yet in any
+      # registered MultibodyComponents release. Remove this step and bump the
+      # MultibodyComponents compat bound once a release containing the fix is
+      # registered.
+      - name: Use MultibodyComponents from main (pending release with BodyShape fix)
+        run: julia --project=. -e 'using Pkg; Pkg.add(url="git@github.com:JuliaComputing/MultibodyComponents.jl.git", rev="main")'
+        env:
+          JULIA_PKG_USE_CLI_GIT: "true"
+
+      - uses: julia-actions/julia-buildpkg@e3eb439fad4f9aba7da2667e7510e4a46ebc46e1 # v1
+
+      - name: Run tests with virtual display
+        run: DISPLAY=:0 xvfb-run --auto-servernum -s '-screen 0 1024x768x24' julia --project -e 'using Pkg; Pkg.test()'