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>

tests/unit/test_export_runtime_requirements.py

@@ -0,0 +1,45 @@
+import unittest
+from pathlib import Path
+from tempfile import TemporaryDirectory
+from unittest.mock import patch
+
+from utils import export_runtime_requirements
+
+
+class TestExportRuntimeRequirements(unittest.TestCase):
+    def test_load_runtime_requirements_reads_project_dependencies(self):
+        pyproject_content = """
+[project]
+dependencies = [
+    "flask",
+    "requests>=2",
+]
+""".lstrip()
+
+        with TemporaryDirectory() as temp_dir:
+            pyproject_path = Path(temp_dir) / "pyproject.toml"
+            pyproject_path.write_text(pyproject_content, encoding="utf-8")
+
+            requirements = export_runtime_requirements.load_runtime_requirements(
+                pyproject_path
+            )
+
+        self.assertEqual(requirements, ["flask", "requests>=2"])
+
+    def test_main_prints_requirements_from_selected_pyproject(self):
+        pyproject_content = """
+[project]
+dependencies = [
+    "pyyaml",
+]
+""".lstrip()
+
+        with TemporaryDirectory() as temp_dir:
+            pyproject_path = Path(temp_dir) / "pyproject.toml"
+            pyproject_path.write_text(pyproject_content, encoding="utf-8")
+
+            with patch("builtins.print") as mock_print:
+                exit_code = export_runtime_requirements.main([str(pyproject_path)])
+
+        self.assertEqual(exit_code, 0)
+        mock_print.assert_called_once_with("pyyaml")