#1 CI: run unit tests on push to main + on PRs

Gitea Actions workflow at .gitea/workflows/ci.yml.  Spins up an
ubuntu:24.04 container, installs the same apt deps the Dockerfile uses
(build-essential, cmake, ninja-build, libasio-dev, libyaml-cpp-dev,
python3, python3-yaml), checks out, runs cmake + ninja, and executes
the doctest binary.

Runs the same toolchain as the local Docker setup; no docker-in-docker
required.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

.gitea/workflows/ci.yml

@@ -0,0 +1,38 @@
+name: tests
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+
+jobs:
+  build-and-test:
+    runs-on: ubuntu-latest
+    container:
+      image: ubuntu:24.04
+    steps:
+      - name: Install toolchain
+        run: |
+          export DEBIAN_FRONTEND=noninteractive
+          apt-get update
+          apt-get install -y --no-install-recommends \
+            build-essential \
+            cmake \
+            ninja-build \
+            git \
+            libasio-dev \
+            libyaml-cpp-dev \
+            python3 \
+            python3-yaml \
+            ca-certificates
+
+      - uses: actions/checkout@v4
+
+      - name: Configure
+        run: cmake -S . -B build -G Ninja -DCMAKE_BUILD_TYPE=Release
+
+      - name: Build
+        run: cmake --build build
+
+      - name: Unit tests
+        run: build/secsgem_tests