chore(ci): modified CI for Godot stage (#1716)

## Description

This PR adds basic CI for Godot stage via ci.yml.

---------

Co-authored-by: Neko <neko@ayaka.moe>
Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>
Co-authored-by: Qi <shengen.qi@hpe.com>
Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>

.github/workflows/ci.yml

@@ -1,5 +1,4 @@
 name: CI
-
 on:
   push:
     branches:
@@ -23,6 +22,20 @@ jobs:
           node-version: lts/*
           cache: pnpm
 
+    # Setup .NET for Godot C# linting
+      - name: Setup .NET
+        uses: actions/setup-dotnet@v4
+        with:
+          dotnet-version: '8.0.x'
+
+    # Lint Godot C# code
+      - name: Lint Godot C#
+        working-directory: ./engines/stage-tamagotchi-godot
+        run: dotnet format stage-tamagotchi-godot.sln --verify-no-changes
+
+      - run: docker run -v `pwd`:`pwd` -w `pwd` ghcr.io/realm/swiftlint:latest
+        working-directory: ./apps/stage-pocket
+
       - run: pnpm install --frozen-lockfile
       - run: pnpm run lint
       - run: docker run -v `pwd`:`pwd` -w `pwd` ghcr.io/realm/swiftlint:latest
@@ -39,6 +52,9 @@ jobs:
 
           - app_name: stage-tamagotchi
             command: pnpm -F @proj-airi/stage-tamagotchi run build
+            
+          - app_name: stage-tamagotchi-godot
+            command: cd engines/stage-tamagotchi-godot && dotnet restore && dotnet build -c ExportRelease
 
           - app_name: ui-transitions
             command: pnpm -F @proj-airi/ui-transitions run play:build
@@ -65,6 +81,20 @@ jobs:
           node-version: lts/*
           cache: pnpm
 
+      # Setup .NET and Godot
+      - name: Setup .NET
+        if: matrix.app_name == 'stage-tamagotchi-godot'
+        uses: actions/setup-dotnet@v4
+        with:
+          dotnet-version: '8.0.x'
+
+      - name: Setup Godot
+        if: matrix.app_name == 'stage-tamagotchi-godot'
+        uses: chickensoft-games/setup-godot@v2
+        with:
+          version: 4.6.1
+          use-dotnet: true
+
       - run: pnpm install --frozen-lockfile
       - run: pnpm run build:packages
 
@@ -103,4 +133,4 @@ jobs:
         #   base-ref: origin/main         # optional, default: origin/main
         #   fail-on-downgrade: true       # optional, default: true
       - name: Print result
-        run: "echo 'Downgraded: ${{ steps.check.outputs.downgraded }}'"
+        run: "echo 'Downgraded: ${{ steps.check.outputs.downgraded }}'"