feat: Phase 3 — web dashboard, testing, and CI/CD

- Remove multi-marketplace from Phase 3
- Add FastAPI web UI on port 8766 with basic auth
- Add 6 Jinja2 templates (dashboard, keywords, users, ads, stats)
- Add pytest test suite (45 tests, 49% coverage)
- Add GitHub Actions CI/CD workflow
- Update docker-compose.yml to expose web UI port
- Update Dockerfile to include tests

pyproject.toml

@@ -0,0 +1,23 @@
+[project]
+name = "willhaben-tracker"
+version = "0.1.0"
+description = "Telegram bot that tracks willhaben.at listings"
+requires-python = ">=3.11"
+
+[tool.pytest.ini_options]
+testpaths = ["tests"]
+asyncio_mode = "auto"
+asyncio_default_fixture_loop_scope = "function"
+pythonpath = ["src"]
+
+[tool.coverage.run]
+source = ["."]
+omit = ["tests/*", "migrate.py", "entrypoint.sh", "bot.py", "web.py", "main.py"]
+
+[tool.coverage.report]
+fail_under = 50
+show_missing = true
+
+[tool.flake8]
+max-line-length = 120
+exclude = [".git", "__pycache__", "node_modules"]