ci(cmake): add concurrency guard, bump checkout v5, use Ninja everywhere

- ubuntu-cmake: add concurrency cancel-in-progress (stop run pile-up per push)
- all 3: actions/checkout@v4 -> @v5 (Node 24; clears the Node 20 deprecation)
- ubuntu + macos: build with -G Ninja for consistency with Windows and a
  slightly faster build (ninja already present on Ubuntu; add brew ninja on macOS)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.github/workflows/macos-cmake.yml

@@ -36,7 +36,7 @@ jobs:
         shell: bash
 
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v5
       with:
         persist-credentials: false
 
@@ -56,7 +56,7 @@ jobs:
     - name: Install Homebrew dependencies
       run: >
         brew install
-        qt@5 openssl@3 botan@2 sqlcipher miniupnpc
+        ninja qt@5 openssl@3 botan@2 sqlcipher miniupnpc
         json-c asio speex speexdsp ffmpeg
         libxml2 libxslt bzip2 zlib rapidjson doxygen
 
@@ -72,7 +72,7 @@ jobs:
         # qt@5 first so find_package(Qt5) picks the keg-only (correct) config, not a
         # broken Qt5 config that may sit directly under the Homebrew prefix.
         PREFIX="$QT5;$HB";      for d in "$HB"/opt/*;          do PREFIX="$PREFIX;$d"; done
-        cmake -B Build-cmake -S . \
+        cmake -G Ninja -B Build-cmake -S . \
           -DCMAKE_POLICY_VERSION_MINIMUM=3.5 -DCMAKE_BUILD_TYPE=Release \
           -DCMAKE_PREFIX_PATH="$PREFIX" \
           -DQt5_DIR="$QT5/lib/cmake/Qt5" \

.github/workflows/ubuntu-cmake.yml

@@ -22,13 +22,17 @@ on:
     paths-ignore:
     - '**/*.md'
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref }}
+  cancel-in-progress: true
+
 jobs:
   build:
     name: Ubuntu 22.04 / Qt5 / CMake
     runs-on: ubuntu-22.04
 
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v5
 
     # NOTE: no --remote here (on purpose) so the pinned, CMake-enabled commits
     # are checked out. librnp needs --recursive for its nested src/libsexpp.
@@ -66,7 +70,7 @@ jobs:
     # Mirrors the validated local Linux build command.
     - name: CMake configure
       run: >
-        cmake -B Build-cmake -S .
+        cmake -G Ninja -B Build-cmake -S .
         -DCMAKE_POLICY_VERSION_MINIMUM=3.5
         -DCMAKE_BUILD_TYPE=Release
         -DRS_RNPLIB=ON -DRS_JSON_API=ON -DRS_WEBUI=ON

.github/workflows/windows-cmake.yml

@@ -38,7 +38,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
         with:
           persist-credentials: false