ci: add orchestrator compatibility validation workflow

Runs on PRs that touch orchestrator source or bridge files.
Validates:
- Orchestrator source files are in sync with standalone repo
- Bridge file exports exist in both repos
- Orchestrator tests pass in both unity-builder and standalone contexts

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.github/workflows/validate-orchestrator.yml

@@ -0,0 +1,95 @@
+name: Validate Orchestrator Compatibility
+
+on:
+  push:
+    branches: [main, 'release/**', 'feature/**']
+    paths:
+      - 'src/model/orchestrator/**'
+      - 'src/model/build-parameters.ts'
+      - 'src/model/input.ts'
+      - 'src/model/github.ts'
+      - 'src/model/docker.ts'
+      - 'src/model/cli/cli.ts'
+      - 'src/model/cli/cli-functions-repository.ts'
+      - 'src/model/input-readers/**'
+      - 'src/model/shared-types.ts'
+      - 'src/model/image-tag.ts'
+      - 'src/model/action.ts'
+  pull_request:
+    branches: [main, 'release/**']
+    paths:
+      - 'src/model/orchestrator/**'
+      - 'src/model/build-parameters.ts'
+      - 'src/model/input.ts'
+      - 'src/model/github.ts'
+      - 'src/model/docker.ts'
+      - 'src/model/cli/cli.ts'
+      - 'src/model/cli/cli-functions-repository.ts'
+      - 'src/model/input-readers/**'
+      - 'src/model/shared-types.ts'
+      - 'src/model/image-tag.ts'
+      - 'src/model/action.ts'
+
+jobs:
+  validate-orchestrator:
+    name: Orchestrator Compatibility Check
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout unity-builder
+        uses: actions/checkout@v4
+
+      - name: Checkout orchestrator repo
+        uses: actions/checkout@v4
+        with:
+          repository: game-ci/orchestrator
+          path: orchestrator-standalone
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: 20
+          cache: yarn
+
+      - name: Install unity-builder dependencies
+        run: yarn install --frozen-lockfile
+
+      - name: Verify orchestrator source is in sync
+        run: |
+          echo "Comparing orchestrator source files..."
+          # Compare orchestrator source between unity-builder and standalone repo
+          # Exclude interfaces.ts which only exists in standalone
+          DIFF_OUTPUT=$(diff -rq src/model/orchestrator/ orchestrator-standalone/src/model/orchestrator/ --exclude="interfaces.ts" 2>&1 || true)
+          if [ -n "$DIFF_OUTPUT" ]; then
+            echo "::warning::Orchestrator source has diverged from standalone repo:"
+            echo "$DIFF_OUTPUT"
+            echo ""
+            echo "Files that differ:"
+            diff -rq src/model/orchestrator/ orchestrator-standalone/src/model/orchestrator/ --exclude="interfaces.ts" | head -20 || true
+          else
+            echo "✓ All orchestrator source files are in sync"
+          fi
+
+      - name: Verify bridge file compatibility
+        run: |
+          echo "Checking that bridge file exports match unity-builder exports..."
+          # Verify key exports exist in both repos
+          for file in build-parameters input github docker action image-tag; do
+            if [ -f "orchestrator-standalone/src/model/${file}.ts" ]; then
+              echo "✓ Bridge file exists: src/model/${file}.ts"
+            else
+              echo "::error::Missing bridge file in orchestrator: src/model/${file}.ts"
+              exit 1
+            fi
+          done
+
+      - name: Run orchestrator tests in unity-builder context
+        run: |
+          echo "Running orchestrator unit tests..."
+          npx jest --no-cache --testPathPattern="src/model/orchestrator/" --passWithNoTests 2>&1 | tail -5
+
+      - name: Run orchestrator tests in standalone context
+        working-directory: orchestrator-standalone
+        run: |
+          yarn install --frozen-lockfile
+          echo "Running orchestrator standalone tests..."
+          npx jest --no-cache 2>&1 | tail -5