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>

utils/check_hadolint_sarif.py

@@ -0,0 +1,28 @@
+#!/usr/bin/env python3
+"""Fail when a hadolint SARIF report contains warnings or errors."""
+
+from __future__ import annotations
+
+import json
+import sys
+from pathlib import Path
+
+
+def main(argv: list[str] | None = None) -> int:
+    args = argv if argv is not None else sys.argv[1:]
+    sarif_path = Path(args[0] if args else "hadolint-results.sarif")
+
+    with sarif_path.open("r", encoding="utf-8") as handle:
+        sarif = json.load(handle)
+
+    results = sarif.get("runs", [{}])[0].get("results", [])
+    levels = [result.get("level", "") for result in results]
+    warnings = sum(1 for level in levels if level == "warning")
+    errors = sum(1 for level in levels if level == "error")
+
+    print(f"SARIF results: total={len(results)} warnings={warnings} errors={errors}")
+    return 1 if warnings + errors > 0 else 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())