Add versioning strategy and CI/CD pipeline

- Add semantic versioning section to development plan
- Map sprint milestones to version tags
- Create Gitea Actions CI workflow (lint, typecheck, test, release)
- Add CHANGELOG.md following Keep a Changelog format

.gitea/workflows/ci.yaml

@@ -0,0 +1,97 @@
+name: CI
+
+on:
+  push:
+    branches: [master, main]
+    tags: ['v*']
+  pull_request:
+    branches: [master, main]
+
+jobs:
+  lint:
+    name: Lint
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: '3.11'
+
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          pip install ruff
+
+      - name: Run Ruff
+        run: ruff check src/ tests/
+
+  typecheck:
+    name: Type Check
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: '3.11'
+
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          pip install -e ".[dev]"
+
+      - name: Run mypy
+        run: mypy src/
+
+  test:
+    name: Test
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: '3.11'
+
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          pip install -e ".[dev]"
+
+      - name: Run pytest
+        run: pytest --cov=src/py_dvt_ate --cov-report=xml
+
+      - name: Check coverage
+        run: |
+          coverage report --fail-under=80 || echo "Coverage below 80% - will enforce after MVP"
+
+  release:
+    name: Release
+    needs: [lint, typecheck, test]
+    if: startsWith(github.ref, 'refs/tags/v')
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: '3.11'
+
+      - name: Install build tools
+        run: |
+          python -m pip install --upgrade pip
+          pip install build
+
+      - name: Build package
+        run: python -m build
+
+      - name: Create Release
+        uses: softprops/action-gh-release@v1
+        with:
+          files: dist/*
+          generate_release_notes: true