feat: migrate to pyproject.toml, add test suites, split CI workflows

- Replace requirements.txt with pyproject.toml for modern Python packaging
- Add unit, integration, lint and security test suites under tests/
- Add utils/export_runtime_requirements.py and utils/check_hadolint_sarif.py
- Split monolithic CI into reusable lint.yml, security.yml and tests.yml
- Refactor ci.yml to orchestrate reusable workflows; publish on semver tag only
- Modernize Dockerfile: pin python:3.12-slim, install via pyproject.toml
- Expand Makefile with lint, security, test and CI targets
- Add test-e2e via act with portfolio container stop/start around run
- Fix navbar_logo_visibility.spec.js: win.fullscreen() → win.enterFullscreen()
- Set use_reloader=False in app.run() to prevent double-start in CI
- Add app/core.* and build artifacts to .gitignore
- Fix apt-get → sudo apt-get in tests.yml e2e job
- Fix pip install --ignore-installed to handle stale act cache

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.github/workflows/lint.yml

@@ -0,0 +1,77 @@
+name: Lint
+
+on:
+  workflow_call:
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+jobs:
+  lint-actions:
+    name: Lint GitHub Actions
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v6
+
+      - name: Run actionlint
+        run: docker run --rm -v "$PWD:/repo" -w /repo rhysd/actionlint:latest
+
+  lint-python:
+    name: Lint Python
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v6
+
+      - name: Set up Python
+        uses: actions/setup-python@v6
+        with:
+          python-version: "3.12"
+
+      - name: Install lint dependencies
+        run: |
+          python -m pip install --upgrade pip
+          pip install ".[dev]"
+
+      - name: Ruff lint
+        run: ruff check .
+
+      - name: Ruff format check
+        run: ruff format --check .
+
+  lint-docker:
+    name: Lint Dockerfile
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      security-events: write
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v6
+
+      - name: Run hadolint
+        id: hadolint
+        continue-on-error: true
+        uses: hadolint/hadolint-action@2332a7b74a6de0dda2e2221d575162eba76ba5e5
+        with:
+          dockerfile: ./Dockerfile
+          format: sarif
+          output-file: hadolint-results.sarif
+          failure-threshold: warning
+
+      - name: Upload hadolint SARIF
+        if: always() && github.event_name == 'push'
+        uses: github/codeql-action/upload-sarif@v4
+        with:
+          sarif_file: hadolint-results.sarif
+          wait-for-processing: true
+          category: hadolint
+
+      - name: Fail on hadolint warnings
+        if: always()
+        run: python3 utils/check_hadolint_sarif.py hadolint-results.sarif