ci: add GitHub Actions workflow for Linux build

Adds automated CI workflow that:
- Builds on Ubuntu 24.04 with apt packages
- Uses ccache for faster rebuilds
- Uploads binary artifact on success

Dependencies: wxWidgets 3.2, Boost, OpenGL, asio, nlohmann-json, fmt

Author: shishiv

.github/workflows/build.yml

@@ -0,0 +1,69 @@
+name: Build RME
+
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+    branches:
+      - master
+
+jobs:
+  build-linux:
+    runs-on: ubuntu-24.04
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Install dependencies
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y \
+            build-essential \
+            cmake \
+            ccache \
+            libasio-dev \
+            nlohmann-json3-dev \
+            libfmt-dev \
+            libboost-system-dev \
+            libboost-thread-dev \
+            libwxgtk3.2-dev \
+            libglu1-mesa-dev \
+            freeglut3-dev \
+            libarchive-dev \
+            zlib1g-dev \
+            libxmu-dev \
+            libxi-dev
+
+      - name: Setup ccache
+        run: |
+          echo "/usr/lib/ccache" >> $GITHUB_PATH
+          mkdir -p ~/.ccache
+          ccache --max-size=500M
+          ccache --set-config=compression=true
+
+      - name: Cache ccache
+        uses: actions/cache@v4
+        with:
+          path: ~/.ccache
+          key: ccache-rme-${{ runner.os }}-${{ github.sha }}
+          restore-keys: |
+            ccache-rme-${{ runner.os }}-
+
+      - name: Build RME
+        run: |
+          mkdir -p build
+          cd build
+          cmake .. -DCMAKE_CXX_COMPILER_LAUNCHER=ccache -DCMAKE_BUILD_TYPE=Release
+          make -j$(nproc)
+
+      - name: Show ccache stats
+        run: ccache --show-stats
+
+      - name: Upload RME binary
+        uses: actions/upload-artifact@v4
+        with:
+          name: rme-linux
+          path: build/rme
+          retention-days: 30