feat(#37): Add Unity test foundation and CI workflow

.github/workflows/unity-tests.yml

@@ -0,0 +1,85 @@
+name: Unity Tests
+
+on:
+  pull_request:
+    branches:
+      - main
+    paths:
+      - "GGJ26/**"
+      - ".github/workflows/unity-tests.yml"
+  workflow_dispatch:
+
+permissions:
+  contents: read
+  checks: write
+
+jobs:
+  unity-tests:
+    name: Unity Tests
+    runs-on: ubuntu-latest
+    timeout-minutes: 60
+    steps:
+      - name: Free disk space
+        run: |
+          sudo rm -rf /usr/share/dotnet /usr/local/lib/android /opt/ghc /opt/hostedtoolcache/CodeQL
+          sudo docker image prune --all --force
+
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          lfs: true
+
+      - name: Cache Library
+        uses: actions/cache@v4
+        with:
+          path: GGJ26/Library
+          key: Library-${{ hashFiles('GGJ26/Assets/**', 'GGJ26/Packages/manifest.json', 'GGJ26/ProjectSettings/**') }}
+          restore-keys: |
+            Library-
+
+      - name: Run EditMode tests
+        id: editmode
+        uses: game-ci/unity-test-runner@v4
+        env:
+          UNITY_LICENSE: ${{ secrets.UNITY_LICENSE }}
+          UNITY_EMAIL: ${{ secrets.UNITY_EMAIL }}
+          UNITY_PASSWORD: ${{ secrets.UNITY_PASSWORD }}
+        with:
+          projectPath: GGJ26
+          testMode: EditMode
+          unityVersion: auto
+          githubToken: ${{ secrets.GITHUB_TOKEN }}
+          checkName: EditMode Test Results
+
+      - name: Upload EditMode artifacts
+        if: always()
+        uses: actions/upload-artifact@v4
+        with:
+          name: unity-editmode-results
+          path: ${{ steps.editmode.outputs.artifactsPath }}
+          if-no-files-found: warn
+          retention-days: 7
+
+      - name: Run PlayMode tests
+        id: playmode
+        if: always()
+        uses: game-ci/unity-test-runner@v4
+        env:
+          UNITY_LICENSE: ${{ secrets.UNITY_LICENSE }}
+          UNITY_EMAIL: ${{ secrets.UNITY_EMAIL }}
+          UNITY_PASSWORD: ${{ secrets.UNITY_PASSWORD }}
+        with:
+          projectPath: GGJ26
+          testMode: PlayMode
+          unityVersion: auto
+          githubToken: ${{ secrets.GITHUB_TOKEN }}
+          checkName: PlayMode Test Results
+
+      - name: Upload PlayMode artifacts
+        if: always()
+        uses: actions/upload-artifact@v4
+        with:
+          name: unity-playmode-results
+          path: ${{ steps.playmode.outputs.artifactsPath }}
+          if-no-files-found: warn
+          retention-days: 7

.gitignore

@@ -7,4 +7,12 @@
 # Antigravity
 .agent/
 .gemini/
-scripts/
+scripts/
+
+# Claude code
+.claude/
+CLAUDE.md
+.omc/
+
+# Codex
+.codex/