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/security/test_config_hygiene.py

@@ -0,0 +1,57 @@
+import subprocess
+import unittest
+from pathlib import Path
+
+import yaml
+
+
+class TestConfigHygiene(unittest.TestCase):
+    def setUp(self) -> None:
+        self.repo_root = Path(__file__).resolve().parents[2]
+        self.sample_config_path = self.repo_root / "app" / "config.sample.yaml"
+
+    def _is_tracked(self, path: str) -> bool:
+        result = subprocess.run(
+            ["git", "ls-files", "--error-unmatch", path],
+            cwd=self.repo_root,
+            check=False,
+            capture_output=True,
+            text=True,
+        )
+        return result.returncode == 0
+
+    def _find_values_for_key(self, data, key_name: str):
+        if isinstance(data, dict):
+            for key, value in data.items():
+                if key == key_name:
+                    yield value
+                yield from self._find_values_for_key(value, key_name)
+        elif isinstance(data, list):
+            for item in data:
+                yield from self._find_values_for_key(item, key_name)
+
+    def test_runtime_only_files_are_ignored_and_untracked(self):
+        gitignore_lines = (
+            (self.repo_root / ".gitignore").read_text(encoding="utf-8").splitlines()
+        )
+
+        self.assertIn("app/config.yaml", gitignore_lines)
+        self.assertIn(".env", gitignore_lines)
+        self.assertFalse(self._is_tracked("app/config.yaml"))
+        self.assertFalse(self._is_tracked(".env"))
+
+    def test_sample_config_keeps_the_nasa_api_key_placeholder(self):
+        with self.sample_config_path.open("r", encoding="utf-8") as handle:
+            sample_config = yaml.safe_load(handle)
+
+        nasa_api_keys = list(self._find_values_for_key(sample_config, "nasa_api_key"))
+        self.assertEqual(
+            nasa_api_keys,
+            ["YOUR_REAL_KEY_HERE"],
+            "config.sample.yaml should only contain the documented NASA API key "
+            "placeholder.",
+        )
+
+
+if __name__ == "__main__":
+    unittest.main()