ci: disable tests in CI, rely on precommit hooks instead

Tests are still enforced locally via precommit hooks (mix precommit).
CI now only:
- Builds Docker image
- Pushes to registry
- Updates deployment

Expected CI time: 10-12 minutes (down from 26 minutes)

Trade-off: Faster CI feedback vs relying on local testing before push.

.forgejo/workflows/build.yaml

@@ -8,71 +8,18 @@ on:
 env:
   DOCKER_BUILDKIT: 1
   DOCKER_TLS_CERTDIR: ""
-  MIX_ENV: test
 
 concurrency:
   group: ${{ github.workflow }}-${{ github.ref }}
   cancel-in-progress: true
 
 jobs:
-  test-and-build:
+  build:
     runs-on: ubuntu-22.04
-    env:
-      DATABASE_URL: postgresql://postgres:postgres@postgres:5432/towerops_test
-      ERL_AFLAGS: "-kernel shell_history enabled"
-    services:
-      postgres:
-        image: timescale/timescaledb:latest-pg17
-        env:
-          POSTGRES_USER: postgres
-          POSTGRES_PASSWORD: postgres
-          POSTGRES_DB: towerops_test
-        options: >-
-          --health-cmd pg_isready
-          --health-interval 3s
-          --health-timeout 2s
-          --health-retries 10
-
     steps:
       - name: Checkout code
         uses: actions/checkout@v4
 
-      - name: Set up Elixir
-        uses: https://github.com/erlef/setup-beam@v1
-        with:
-          otp-version: '28.3'
-          elixir-version: '1.19.5'
-          version-type: strict
-
-      - name: Restore caches
-        uses: actions/cache@v4
-        with:
-          path: |
-            ~/.hex
-            ~/.mix
-            deps
-            _build
-            native/towerops_native/target
-            ~/.cargo/registry
-            ~/.cargo/git
-          key: ${{ runner.os }}-mix-${{ hashFiles('**/mix.lock') }}-${{ hashFiles('lib/**/*.ex') }}-${{ hashFiles('native/**/*.rs') }}-elixir-1.19.5-otp-28.3
-          restore-keys: |
-            ${{ runner.os }}-mix-${{ hashFiles('**/mix.lock') }}-
-            ${{ runner.os }}-mix-
-
-      - name: Install system dependencies
-        run: |
-          sudo apt-get update
-          sudo apt-get install -y --no-install-recommends libsnmp-dev snmp-mibs-downloader postgresql-client
-
-      - name: Install Elixir dependencies
-        run: mix deps.get --only test
-
-      - name: Compile and test
-        run: |
-          mix compile --warnings-as-errors
-          mix test --warnings-as-errors --max-cases 3
-
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v3
         with: