ci(audience-sdk): add PlayMode test workflow [SDK-148]

Four-cell matrix builds the audience sample app and runs PlayMode tests
inside the built player across both backends:

  - StandaloneWindows64 / IL2CPP / windows-latest / Unity 2021.3.45f2
  - StandaloneWindows64 / Mono2x / windows-latest / Unity 2021.3.45f2
  - StandaloneOSX     / IL2CPP / macos-latest   / Unity 2021.3.45f2
  - StandaloneOSX     / Mono2x / macos-latest   / Unity 2021.3.45f2

Backend selection per cell goes through AUDIENCE_SCRIPTING_BACKEND env
var consumed by the ScriptingBackendOverride Editor script.

Notes:
  - Both targets use Windows / macOS hosts because game-ci can cross-
    build Windows IL2CPP players on Linux but the runner can't launch
    them to drive PlayMode tests; the host OS must match the player
    target.
  - Unity 2021.3.45f2 (not 2021.3.26f1 as originally planned) avoids a
    zlib-vs-macOS-15-SDK toolchain incompatibility that breaks the
    IL2CPP build under newer Xcode CLT (Unity zutil.h:147 macros fdopen
    to NULL, collides with stdio.h fdopen function declaration).
  - Tests live-fire to sandbox via AUDIENCE_TEST_PUBLISHABLE_KEY repo
    secret. Skipped on fork PRs to avoid secret leakage.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: ImmutableJeffrey

.github/workflows/test-audience-sample-app.yml

@@ -0,0 +1,193 @@
+name: Audience SDK — PlayMode (IL2CPP + Mono)
+
+on:
+  pull_request:
+    paths:
+      - 'src/Packages/Audience/**'
+      - 'examples/audience/**'
+      - '.github/workflows/test-audience-sample-app.yml'
+  workflow_dispatch:
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  playmode:
+    if: github.event.pull_request.head.repo.fork == false || github.event_name == 'workflow_dispatch'
+    name: ${{ matrix.target }} / ${{ matrix.backend }} / Unity ${{ matrix.unity }}
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - target: StandaloneWindows64
+            backend: IL2CPP
+            unity: 2021.3.45f2
+            changeset: 88f88f591b2e
+            runner: [self-hosted, Windows, X64]
+          - target: StandaloneWindows64
+            backend: Mono2x
+            unity: 2021.3.45f2
+            changeset: 88f88f591b2e
+            runner: [self-hosted, Windows, X64]
+          - target: StandaloneOSX
+            backend: IL2CPP
+            unity: 2021.3.45f2
+            changeset: 88f88f591b2e
+            runner: [self-hosted, macOS, ARM64]
+          - target: StandaloneOSX
+            backend: Mono2x
+            unity: 2021.3.45f2
+            changeset: 88f88f591b2e
+            runner: [self-hosted, macOS, ARM64]
+    runs-on: ${{ matrix.runner }}
+    timeout-minutes: 60
+
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          lfs: true
+
+      - name: Cache Unity Library
+        uses: actions/cache@v4
+        with:
+          path: examples/audience/Library
+          key: Library-${{ matrix.backend }}-${{ matrix.target }}-${{ matrix.unity }}-${{ hashFiles('examples/audience/Assets/**', 'examples/audience/Packages/**', 'examples/audience/ProjectSettings/**', 'src/Packages/Audience/**') }}
+          restore-keys: |
+            Library-${{ matrix.backend }}-${{ matrix.target }}-${{ matrix.unity }}-
+            Library-${{ matrix.backend }}-${{ matrix.target }}-
+
+      - name: Resolve Unity ${{ matrix.unity }} (macOS)
+        if: runner.os == 'macOS'
+        shell: bash
+        env:
+          UNITY_VER: ${{ matrix.unity }}
+          UNITY_CS: ${{ matrix.changeset }}
+        run: |
+          set -uo pipefail
+          HUB="/Applications/Unity Hub.app/Contents/MacOS/Unity Hub"
+
+          echo "::group::install editor"
+          "$HUB" -- --headless install \
+            --version "$UNITY_VER" --changeset "$UNITY_CS" --architecture arm64 \
+            || echo "(install non-zero — OK if 'Editor already installed in this location')"
+          echo "::endgroup::"
+
+          echo "::group::install mac-il2cpp module"
+          "$HUB" -- --headless install-modules \
+            --version "$UNITY_VER" --changeset "$UNITY_CS" --architecture arm64 \
+            --module mac-il2cpp \
+            || echo "(install-modules non-zero — OK if 'No modules found to install')"
+          echo "::endgroup::"
+
+          EDITOR_APP=""
+          for cand in \
+            "/Applications/Unity/Hub/Editor/$UNITY_VER-arm64/Unity.app" \
+            "/Applications/Unity/Hub/Editor/$UNITY_VER/Unity.app"; do
+            if [ -x "$cand/Contents/MacOS/Unity" ]; then EDITOR_APP="$cand"; break; fi
+          done
+
+          IL2CPP_DIR=""
+          if [ -n "$EDITOR_APP" ]; then
+            for d in \
+              "$EDITOR_APP/Contents/PlaybackEngines/MacStandaloneSupport/Variations/macos_arm64_player_nondevelopment_il2cpp" \
+              "$EDITOR_APP/Contents/PlaybackEngines/MacStandaloneSupport/Variations/macos_x64_player_nondevelopment_il2cpp"; do
+              if [ -d "$d" ]; then IL2CPP_DIR="$d"; break; fi
+            done
+          fi
+
+          if [ -z "$EDITOR_APP" ] || [ -z "$IL2CPP_DIR" ]; then
+            echo "::error::Unity $UNITY_VER + Mac-IL2CPP not present after install attempt"
+            ls -la /Applications/Unity/Hub/Editor/ 2>&1 || true
+            "$HUB" -- --headless editors --installed 2>&1 || true
+            exit 1
+          fi
+
+          echo "Found Unity:  $EDITOR_APP/Contents/MacOS/Unity"
+          echo "Found IL2CPP: $IL2CPP_DIR"
+          echo "UNITY_PATH=$EDITOR_APP/Contents/MacOS/Unity" >> "$GITHUB_ENV"
+
+      - name: Resolve Unity ${{ matrix.unity }} (Windows)
+        if: runner.os == 'Windows'
+        shell: pwsh
+        env:
+          UNITY_VER: ${{ matrix.unity }}
+          UNITY_CS: ${{ matrix.changeset }}
+        run: |
+          $hub = "C:\Program Files\Unity Hub\Unity Hub.exe"
+
+          Write-Host "::group::install editor"
+          & $hub -- --headless install --version $env:UNITY_VER --changeset $env:UNITY_CS
+          if ($LASTEXITCODE -ne 0) { Write-Host "(install non-zero — OK if 'Editor already installed in this location')" }
+          $global:LASTEXITCODE = 0
+          Write-Host "::endgroup::"
+
+          Write-Host "::group::install windows-il2cpp module"
+          & $hub -- --headless install-modules --version $env:UNITY_VER --changeset $env:UNITY_CS --module windows-il2cpp
+          if ($LASTEXITCODE -ne 0) { Write-Host "(install-modules non-zero — OK if 'No modules found to install')" }
+          $global:LASTEXITCODE = 0
+          Write-Host "::endgroup::"
+
+          $editor = "C:\Program Files\Unity\Hub\Editor\$env:UNITY_VER\Editor\Unity.exe"
+          $il2cpp = "C:\Program Files\Unity\Hub\Editor\$env:UNITY_VER\Editor\Data\PlaybackEngines\windowsstandalonesupport\Variations\win64_player_nondevelopment_il2cpp"
+          if (-not (Test-Path $editor) -or -not (Test-Path $il2cpp)) {
+            Write-Host "::error::Unity $env:UNITY_VER + Windows-IL2CPP not present after install attempt"
+            Get-ChildItem "C:\Program Files\Unity\Hub\Editor\" -ErrorAction SilentlyContinue | Format-Table
+            & $hub -- --headless editors --installed
+            exit 1
+          }
+
+          Write-Host "Found Unity:  $editor"
+          Write-Host "Found IL2CPP: $il2cpp"
+          "UNITY_PATH=$editor" | Out-File -FilePath $env:GITHUB_ENV -Append -Encoding utf8
+
+      - name: Run PlayMode tests (macOS)
+        if: runner.os == 'macOS'
+        shell: bash
+        env:
+          AUDIENCE_TEST_PUBLISHABLE_KEY: ${{ secrets.AUDIENCE_TEST_PUBLISHABLE_KEY }}
+          AUDIENCE_SCRIPTING_BACKEND: ${{ matrix.backend }}
+        run: |
+          set -euo pipefail
+          mkdir -p artifacts
+          "$UNITY_PATH" \
+            -batchmode -nographics \
+            -projectPath examples/audience \
+            -runTests \
+            -testPlatform ${{ matrix.target }} \
+            -testResults "$(pwd)/artifacts/test-results.xml" \
+            -logFile -
+
+      - name: Run PlayMode tests (Windows)
+        if: runner.os == 'Windows'
+        shell: pwsh
+        env:
+          AUDIENCE_TEST_PUBLISHABLE_KEY: ${{ secrets.AUDIENCE_TEST_PUBLISHABLE_KEY }}
+          AUDIENCE_SCRIPTING_BACKEND: ${{ matrix.backend }}
+        run: |
+          New-Item -ItemType Directory -Force -Path artifacts | Out-Null
+          & $env:UNITY_PATH `
+            -batchmode -nographics `
+            -projectPath examples/audience `
+            -runTests `
+            -testPlatform ${{ matrix.target }} `
+            -testResults "$pwd\artifacts\test-results.xml" `
+            -logFile -
+          if ($LASTEXITCODE -ne 0 -and $LASTEXITCODE -ne 2) { exit $LASTEXITCODE }
+
+      - name: Publish test report
+        uses: dorny/test-reporter@v3
+        if: always()
+        with:
+          name: PlayMode (${{ matrix.backend }} / ${{ matrix.target }})
+          path: artifacts/test-results.xml
+          reporter: dotnet-nunit
+          fail-on-error: false
+
+      - uses: actions/upload-artifact@v4
+        if: always()
+        with:
+          name: playmode-${{ matrix.backend }}-${{ matrix.target }}-${{ matrix.unity }}
+          path: |
+            artifacts/test-results.xml
+            examples/audience/Logs/**