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_configuration_resolver.py

@@ -0,0 +1,74 @@
+import unittest
+
+from app.utils.configuration_resolver import ConfigurationResolver
+
+
+class TestConfigurationResolver(unittest.TestCase):
+    def test_resolve_links_replaces_mapping_link_with_target_object(self):
+        config = {
+            "profiles": [
+                {"name": "Mastodon", "url": "https://example.com/@user"},
+            ],
+            "featured": {"link": "profiles.mastodon"},
+        }
+
+        resolver = ConfigurationResolver(config)
+        resolver.resolve_links()
+
+        self.assertEqual(
+            resolver.get_config()["featured"],
+            {"name": "Mastodon", "url": "https://example.com/@user"},
+        )
+
+    def test_resolve_links_expands_children_link_to_list_entries(self):
+        config = {
+            "accounts": {
+                "children": [
+                    {"name": "Matrix", "url": "https://matrix.example"},
+                    {"name": "Signal", "url": "https://signal.example"},
+                ]
+            },
+            "navigation": {
+                "children": [
+                    {"link": "accounts.children"},
+                ]
+            },
+        }
+
+        resolver = ConfigurationResolver(config)
+        resolver.resolve_links()
+
+        self.assertEqual(
+            resolver.get_config()["navigation"]["children"],
+            [
+                {"name": "Matrix", "url": "https://matrix.example"},
+                {"name": "Signal", "url": "https://signal.example"},
+            ],
+        )
+
+    def test_resolve_links_rejects_non_list_children(self):
+        config = {"navigation": {"children": {"name": "Invalid"}}}
+
+        resolver = ConfigurationResolver(config)
+
+        with self.assertRaises(ValueError):
+            resolver.resolve_links()
+
+    def test_find_entry_handles_case_and_space_insensitive_paths(self):
+        config = {
+            "Social Networks": {
+                "children": [
+                    {"name": "Friendica", "url": "https://friendica.example"},
+                ]
+            }
+        }
+
+        resolver = ConfigurationResolver(config)
+
+        entry = resolver._find_entry(config, "socialnetworks.friendica", False)
+
+        self.assertEqual(entry["url"], "https://friendica.example")
+
+
+if __name__ == "__main__":
+    unittest.main()