Enhance testing framework and UI feedback

- Updated architecture documentation to include details on UI rendering checks and Playwright end-to-end tests.
- Revised testing documentation to specify Playwright for frontend E2E tests and added details on running tests.
- Implemented feedback mechanism in scenario form for successful creation notifications.
- Added feedback div in ScenarioForm.html for user notifications.
- Created new fixtures for Playwright tests to manage server and browser instances.
- Developed comprehensive E2E tests for consumption, costs, equipment, maintenance, production, and scenarios.
- Added smoke tests to verify UI page loading and form submissions.
- Enhanced unit tests for simulation and validation, including new tests for report generation and validation errors.
- Created new test files for router validation to ensure consistent error handling.
- Established a new test suite for UI routes to validate dashboard and reporting functionalities.
- Implemented validation tests to ensure proper handling of JSON payloads.

tests/e2e/test_smoke.py

@@ -0,0 +1,29 @@
+import pytest
+from playwright.sync_api import Page, expect
+
+# A list of UI routes to check, with their URL, expected title, and a key heading text.
+UI_ROUTES = [
+    ("/", "CalMiner Dashboard", "Dashboard"),
+    ("/ui/dashboard", "CalMiner Dashboard", "Dashboard"),
+    ("/ui/scenarios", "CalMiner Scenarios", "Scenarios"),
+    ("/ui/parameters", "CalMiner Parameters", "Parameters"),
+    ("/ui/costs", "CalMiner Costs", "Costs"),
+    ("/ui/consumption", "CalMiner Consumption", "Consumption"),
+    ("/ui/production", "CalMiner Production", "Production"),
+    ("/ui/equipment", "CalMiner Equipment", "Equipment"),
+    ("/ui/maintenance", "CalMiner Maintenance", "Maintenance"),
+    ("/ui/simulations", "CalMiner Simulations", "Simulations"),
+    ("/ui/reporting", "CalMiner Reporting", "Reporting"),
+]
+
+
+@pytest.mark.usefixtures("live_server")
+@pytest.mark.parametrize("url, title, heading", UI_ROUTES)
+def test_ui_pages_load_correctly(page: Page, url: str, title: str, heading: str):
+    """Verify that all UI pages load with the correct title and a visible heading."""
+    page.goto(url)
+    expect(page).to_have_title(title)
+    # The app uses a mix of h1 and h2 for main page headings.
+    heading_locator = page.locator(
+        f"h1:has-text('{heading}'), h2:has-text('{heading}')")
+    expect(heading_locator.first).to_be_visible()