fix(ci): Cat-1 — install cmake/build-essential + drop windows matrix

First-run revealed:
1. Runner images (catthehacker/ubuntu:act-latest) lack cmake.
   Added apt-get install step (cmake, build-essential, ninja-build,
   zip, unzip, git, curl).
2. windows-latest matrix entry mapped to Linux fallback containers
   (Davoryn runner pool currently Linux-only). Dropped from matrix
   until Windows runner provisioned.

Other workflows (Cat-2 hybrid, etc.) likely need same fix when first
exercised — apply iteratively as consumers come online.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.gitea/workflows/reusable-engine-launcher.yml

@@ -19,12 +19,20 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ubuntu-latest, windows-latest]
+        # Windows entry deferred — Davoryn runner pool currently Linux-only.
+        # Re-add 'windows-latest' once a Windows runner is provisioned.
+        os: [ubuntu-latest]
     runs-on: ${{ matrix.os }}
     steps:
       - name: Checkout
         uses: actions/checkout@v4
 
+      - name: Install build tools (Linux)
+        if: runner.os == 'Linux'
+        run: |
+          apt-get update -qq
+          apt-get install -y cmake build-essential ninja-build zip unzip git curl
+
       - name: Configure CMake
         run: cmake -B build -DCMAKE_BUILD_TYPE=${{ inputs.build_type }}