finish refactor, add docs and CI

.github/workflows/build.yml

@@ -0,0 +1,76 @@
+name: CI
+
+on:
+  push:
+  pull_request:
+
+jobs:
+  nro:
+    name: Build NRO
+    runs-on: ubuntu-latest
+    container:
+      image: devkitpro/devkita64:latest
+
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          submodules: recursive
+
+      - name: Configure
+        run: cmake --preset switch
+
+      - name: Build
+        run: cmake --build build -j$(nproc)
+
+      - uses: actions/upload-artifact@v4
+        with:
+          name: NXST-${{ github.sha }}
+          path: build/NXST.nro
+
+  release:
+    name: Upload release asset
+    runs-on: ubuntu-latest
+    needs: nro
+    if: startsWith(github.ref, 'refs/tags/v')
+
+    permissions:
+      contents: write
+
+    steps:
+      - uses: actions/download-artifact@v4
+        with:
+          name: NXST-${{ github.sha }}
+
+      - uses: softprops/action-gh-release@v2
+        with:
+          files: NXST.nro
+
+  format:
+    name: Format check
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install clang-format
+        run: |
+          wget -qO- https://apt.llvm.org/llvm-snapshot.gpg.key | sudo tee /etc/apt/trusted.gpg.d/apt.llvm.org.asc
+          echo "deb http://apt.llvm.org/noble/ llvm-toolchain-noble-22 main" | sudo tee /etc/apt/sources.list.d/llvm.list
+          sudo apt-get update && sudo apt-get install -y clang-format-22
+          sudo ln -sf /usr/bin/clang-format-22 /usr/local/bin/clang-format
+
+      - name: Check formatting
+        run: |
+          find src include \( -name '*.cpp' -o -name '*.hpp' \) \
+            | xargs clang-format --dry-run --Werror
+
+  layering:
+    name: Layering check
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: UI must not include net/sys headers
+        run: |
+          ! grep -rE '^#include\s*[<"](arpa/inet|sys/socket|pthread)' src/ui/