ci(audience): restore PlayMode cells, trim mobile on PR, harden Windows pre-checkout (SDK-330)

- Replaces the cross-product matrix (unity x target x backend with
  axis-matching include items) on `playmode` with a `set-matrix` helper
  job that emits a fully-specified JSON matrix.
- The cross-product approach silently expanded to zero playmode cells
  on every run since SDK-327, so Windows and macOS PlayMode tests have
  not actually run on PRs (verified on the SDK-327 merge commit and on
  PR #748). Root cause: a unity-keyed include item that has no cell to
  augment after the conditional `exclude` removes Unity 2022 on PR runs
  spawns an orphan combination missing `target`, `backend`, and
  `runner`; `runs-on: ${{ matrix.runner }}` then evaluates to empty and
  GitHub aborts the matrix.
- `set-matrix` runs on ubuntu-latest, defines the full 12-cell playmode
  matrix and 6-cell mobile matrix inline as JSON, and uses jq to strip
  Unity 2022.3.62f2 cells when the trigger is pull_request. Schedule
  and workflow_dispatch get the full sets.
- `playmode` declares `needs: set-matrix` and consumes via
  `matrix.include: fromJSON(needs.set-matrix.outputs.playmode)`. Each
  cell carries every key the steps need (target, backend, unity,
  changeset, runner), so no augmentation step can silently drop keys.
- `mobile-build` declares `needs: set-matrix` and consumes
  `needs.set-matrix.outputs.mobile`. PR runs drop Unity 2022.3.62f2 to
  match the playmode and playmode-linux trim. Schedule and
  workflow_dispatch keep the full 3 Unity versions.
- Hardens the Windows pre-checkout cleanup. The previous Kill-stale step
  only covered Unity-family processes and slept 2 seconds, then handed
  off to actions/checkout@v4 which would die with EBUSY on stuck files
  in examples/audience. New step adds bee_backend and mono to the kill
  list, sleeps 3 seconds, and force-removes the workspace contents in a
  retry loop so checkout's own cleanup is left with nothing to do.
- mobile-build job steps unchanged. mobile-build trigger fix (the
  `null == false` coercion) lives in SDK-329 / PR #748 and rebases on
  this hot-fix.
- playmode-linux untouched: its existing cross-product + conditional
  exclude pattern works because it has no axis-matching include items
  and `runs-on` is hardcoded.

Linear: https://linear.app/imtbl/issue/SDK-330

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

Author: ImmutableJeffrey

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

@@ -26,11 +26,52 @@ concurrency:
   cancel-in-progress: true
 
 jobs:
-  # Reduced matrix on pull_request, full matrix on schedule and
-  # workflow_dispatch. The self-hosted Windows runner pool is small, so
-  # trimming PR cells keeps PR feedback fast. `matrix.exclude` below is
-  # the source of truth for which cells are dropped on pull_request.
+  # The PlayMode and mobile-build matrices are built here and consumed
+  # by the dependent jobs via fromJSON. PR runs trim Unity 2022.3.62f2
+  # cells; schedule and workflow_dispatch run the full set.
+  set-matrix:
+    runs-on: ubuntu-latest
+    outputs:
+      playmode: ${{ steps.set.outputs.playmode }}
+      mobile: ${{ steps.set.outputs.mobile }}
+    steps:
+      - id: set
+        shell: bash
+        run: |
+          playmode_full='[
+            {"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"]},
+            {"target":"StandaloneWindows64","backend":"IL2CPP","unity":"6000.4.0f1","changeset":"8cf496087c8f","runner":["self-hosted","Windows","X64"]},
+            {"target":"StandaloneWindows64","backend":"Mono2x","unity":"6000.4.0f1","changeset":"8cf496087c8f","runner":["self-hosted","Windows","X64"]},
+            {"target":"StandaloneOSX","backend":"IL2CPP","unity":"6000.4.0f1","changeset":"8cf496087c8f","runner":["self-hosted","macOS","ARM64"]},
+            {"target":"StandaloneOSX","backend":"Mono2x","unity":"6000.4.0f1","changeset":"8cf496087c8f","runner":["self-hosted","macOS","ARM64"]},
+            {"target":"StandaloneWindows64","backend":"IL2CPP","unity":"2022.3.62f2","changeset":"7670c08855a9","runner":["self-hosted","Windows","X64"]},
+            {"target":"StandaloneWindows64","backend":"Mono2x","unity":"2022.3.62f2","changeset":"7670c08855a9","runner":["self-hosted","Windows","X64"]},
+            {"target":"StandaloneOSX","backend":"IL2CPP","unity":"2022.3.62f2","changeset":"7670c08855a9","runner":["self-hosted","macOS","ARM64"]},
+            {"target":"StandaloneOSX","backend":"Mono2x","unity":"2022.3.62f2","changeset":"7670c08855a9","runner":["self-hosted","macOS","ARM64"]}
+          ]'
+          mobile_full='[
+            {"target":"Android","unity":"2021.3.45f2","method":"AndroidBuilder.Build"},
+            {"target":"Android","unity":"2022.3.62f2","method":"AndroidBuilder.Build"},
+            {"target":"Android","unity":"6000.4.5f1","method":"AndroidBuilder.Build"},
+            {"target":"iOS","unity":"2021.3.45f2","method":"IosBuilder.Build"},
+            {"target":"iOS","unity":"2022.3.62f2","method":"IosBuilder.Build"},
+            {"target":"iOS","unity":"6000.4.5f1","method":"IosBuilder.Build"}
+          ]'
+          if [[ "${{ github.event_name }}" == "pull_request" ]]; then
+            playmode=$(jq -c '[.[] | select(.unity != "2022.3.62f2")]' <<<"$playmode_full")
+            mobile=$(jq -c '[.[] | select(.unity != "2022.3.62f2")]' <<<"$mobile_full")
+          else
+            playmode=$(jq -c '.' <<<"$playmode_full")
+            mobile=$(jq -c '.' <<<"$mobile_full")
+          fi
+          echo "playmode=$playmode" >> "$GITHUB_OUTPUT"
+          echo "mobile=$mobile" >> "$GITHUB_OUTPUT"
+
   playmode:
+    needs: set-matrix
     if: |
       (github.event_name == 'pull_request' && github.event.pull_request.head.repo.fork == false)
       || github.event_name == 'schedule'
@@ -39,21 +80,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        unity: ['2021.3.45f2', '6000.4.0f1', '2022.3.62f2']
-        target: [StandaloneWindows64, StandaloneOSX]
-        backend: [IL2CPP, Mono2x]
-        include:
-          - unity: '2021.3.45f2'
-            changeset: 88f88f591b2e
-          - unity: '6000.4.0f1'
-            changeset: 8cf496087c8f
-          - unity: '2022.3.62f2'
-            changeset: 7670c08855a9
-          - target: StandaloneWindows64
-            runner: [self-hosted, Windows, X64]
-          - target: StandaloneOSX
-            runner: [self-hosted, macOS, ARM64]
-        exclude: ${{ fromJSON(github.event_name == 'pull_request' && '[{"unity":"2022.3.62f2"}]' || '[]') }}
+        include: ${{ fromJSON(needs.set-matrix.outputs.playmode) }}
     runs-on: ${{ matrix.runner }}
     # Healthy cells finish in ~10 min. 30 min covers cold caches +
     # IL2CPP + Unity 6 startup; anything past that is a hang. Capping
@@ -62,25 +89,43 @@ jobs:
     timeout-minutes: 30
 
     steps:
-      - name: Kill stale Unity processes (Windows pre-checkout)
+      - name: Clean Windows workspace (pre-checkout)
         if: runner.os == 'Windows'
         shell: pwsh
         continue-on-error: true
         run: |
-          # actions/checkout@v4 deletes the prior workspace before cloning. If a
-          # previous run's Unity Editor / IL2CPP build process is still holding
-          # handles inside examples/audience, checkout dies with EBUSY. Kill any
-          # leftover Unity-family process here so checkout's cleanup succeeds.
+          # actions/checkout@v4 removes the prior workspace before cloning. If
+          # a previous run's Unity build / IL2CPP linker / bee_backend / shader
+          # compiler is still holding handles, checkout dies with EBUSY on
+          # examples/audience. Kill known offenders, then force-remove the
+          # workspace contents ourselves so checkout's cleanup succeeds.
           Get-Process | Where-Object {
             $_.Name -like 'Unity*' -or
             $_.Name -like 'il2cpp*' -or
             $_.Name -like 'UnityShaderCompiler*' -or
-            $_.Name -like 'UnityCrashHandler*'
+            $_.Name -like 'UnityCrashHandler*' -or
+            $_.Name -like 'bee_backend*' -or
+            $_.Name -like 'mono*'
           } | ForEach-Object {
             Write-Host "Killing stale process: $($_.Name) (pid $($_.Id))"
             Stop-Process -Id $_.Id -Force -ErrorAction SilentlyContinue
           }
-          Start-Sleep -Seconds 2
+          Start-Sleep -Seconds 3
+
+          $ws = "$env:GITHUB_WORKSPACE"
+          if (-not (Test-Path $ws)) { return }
+          for ($i = 1; $i -le 6; $i++) {
+            try {
+              Get-ChildItem -Path $ws -Force -ErrorAction Stop |
+                Remove-Item -Recurse -Force -ErrorAction Stop
+              Write-Host "Cleaned $ws on attempt ${i}"
+              return
+            } catch {
+              Write-Host "Attempt ${i}: $($_.Exception.Message)"
+              Start-Sleep -Seconds 3
+            }
+          }
+          Write-Host "::warning::Workspace not fully cleaned; checkout may fail"
 
       - uses: actions/checkout@v4
         with:
@@ -470,6 +515,7 @@ jobs:
   # Note: Unity 6 cells use 6000.4.5f1 (the latest patch with a GameCI image);
   # 6000.4.0f1 does not have a published GameCI Docker image.
   mobile-build:
+    needs: set-matrix
     if: |
       (github.event_name == 'pull_request' && github.event.pull_request.head.repo.fork == false)
       || github.event_name == 'schedule'
@@ -479,13 +525,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        target: [Android, iOS]
-        unity: ['2021.3.45f2', '2022.3.62f2', '6000.4.5f1']
-        include:
-          - target: Android
-            method: AndroidBuilder.Build
-          - target: iOS
-            method: IosBuilder.Build
+        include: ${{ fromJSON(needs.set-matrix.outputs.mobile) }}
 
     steps:
       - uses: actions/checkout@v4