ci: refactor workflows for SonarQube, tag-only Docker builds, and global testing

- Run SonarQube scans only on main, staging, and feat/* branches
- Build and push Docker images only on semantic version tags
- Add test job that runs on all events

.gitea/workflows/testing.yml

@@ -0,0 +1,36 @@
+name: Tests
+
+on:
+  pull_request:
+    types: [opened, synchronize, reopened]
+  issue_comment:
+    types: [created]
+
+jobs:
+  test:
+    name: Run Tests
+    runs-on: ubuntu-latest
+    if: |
+      github.event_name == 'pull_request' ||
+      (github.event_name == 'issue_comment' && 
+       github.event.issue.pull_request != null &&
+       contains(github.event.comment.body, '/retest'))
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Set up Go
+        uses: actions/setup-go@v6
+        with:
+          go-version: 'stable'
+          cache: false
+
+      - name: Install dependencies
+        run: go mod download
+
+      - name: Run go vet
+        run: go vet ./...
+
+      - name: Run tests
+        run: go test -v -p 4 ./...