Update CI to build tests and Linux directly on runner

Replaces Docker-based builds for run-tests and build-linux jobs with
direct apt-get dependency installation and inner build scripts.
Also triggers on pushes to gitea-actions branch.

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

.github/workflows/build.yml

@@ -3,26 +3,70 @@ on:
   push:
     tags:
       - '*'
+    branches:
+      - gitea-actions
 jobs:
   run-tests:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout repository
         uses: actions/checkout@v6
-      - name: Set up Docker
-        uses: docker/setup-docker-action@v5
-      - name: Run tests in Docker
-        run: ./scripts/test-linux-docker.sh
+      - name: Install dependencies
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y \
+            build-essential \
+            cmake \
+            python3 \
+            python3-pip \
+            python3-polib \
+            python3-pil \
+            libsdl2-dev \
+            libgl1-mesa-dev \
+            libzip-dev \
+            python3-dotenv \
+            python3-pyqt5 \
+            python3-opengl \
+            xz-utils \
+            liblzma-dev \
+            libbz2-dev \
+            zlib1g-dev \
+            libbz2-dev \
+            git \
+            libssl-dev
+      - name: Run tests
+        run: ./scripts/test-linux.sh
 
   build-linux:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout repository
         uses: actions/checkout@v6
-      - name: Set up Docker
-        uses: docker/setup-docker-action@v5
+      - name: Install dependencies
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y \
+            build-essential \
+            cmake \
+            python3 \
+            python3-pip \
+            python3-polib \
+            python3-pil \
+            libsdl2-dev \
+            libgl1-mesa-dev \
+            libzip-dev \
+            python3-dotenv \
+            python3-pyqt5 \
+            python3-opengl \
+            xz-utils \
+            liblzma-dev \
+            libbz2-dev \
+            zlib1g-dev \
+            libbz2-dev \
+            git \
+            libssl-dev
       - name: Build Linux
-        run: ./scripts/build-linux-docker.sh
+        run: ./scripts/build-linux.sh
       - name: Upload Linux binary
         uses: actions/upload-artifact@v6
         with: