Add HTML templates for dashboard, metrics, overview, and backtesting

- Introduced new HTML templates for the dashboard, metrics, overview, and backtesting functionalities.
- Implemented partial templates for metrics, overview, audit, controls, and charts to enhance modularity.
- Updated the Jinja2 template resolution logic to support different deployment environments.
- Added a health check template to display the service status.
- Included a test suite to verify the template resolution logic.
- Updated `pyproject.toml` to include new HTML templates in the package data.

tests/unit/test_template_resolution.py

@@ -0,0 +1,19 @@
+from importlib import resources
+from pathlib import Path
+
+from arbitrade.api import routes
+
+
+def test_template_directory_resolves_to_existing_location() -> None:
+    template_dir = Path(routes._resolve_templates_directory())
+
+    assert template_dir.is_dir()
+    assert (template_dir / "dashboard.html").is_file()
+
+
+def test_template_exists_in_package_resources() -> None:
+    template_path = resources.files("arbitrade").joinpath(
+        "web", "templates", "dashboard.html"
+    )
+
+    assert template_path.is_file()