feat(navigation): Enhance navigation links and add legacy route redirects

- Updated navigation links in `init_db.py` to include href overrides and parent slugs for profitability, opex, and capex planners.
- Modified `NavigationService` to handle child links and href overrides, ensuring proper routing when context is missing.
- Adjusted scenario detail and list templates to use new route names for opex and capex forms, with legacy fallbacks.
- Introduced integration tests for legacy calculation routes to ensure proper redirection and error handling.
- Added tests for navigation sidebar to validate role-based access and link visibility.
- Enhanced navigation sidebar tests to include calculation links and contextual URLs based on project and scenario IDs.

scripts/init_db.py

@@ -657,27 +657,33 @@ DEFAULT_NAVIGATION_LINKS: list[NavigationLinkSeed] = [
         group_slug="workspace",
         label="Profitability Calculator",
         route_name="calculations.profitability_form",
+        href_override="/calculations/profitability",
         match_prefix="/calculations/profitability",
         sort_order=50,
         required_roles=["analyst", "admin"],
+        parent_slug="projects",
     ),
     NavigationLinkSeed(
         slug="opex",
         group_slug="workspace",
         label="Opex Planner",
         route_name="calculations.opex_form",
+        href_override="/calculations/opex",
         match_prefix="/calculations/opex",
         sort_order=60,
         required_roles=["analyst", "admin"],
+        parent_slug="projects",
     ),
     NavigationLinkSeed(
         slug="capex",
         group_slug="workspace",
         label="Capex Planner",
         route_name="calculations.capex_form",
+        href_override="/calculations/capex",
         match_prefix="/calculations/capex",
         sort_order=70,
         required_roles=["analyst", "admin"],
+        parent_slug="projects",
     ),
     NavigationLinkSeed(
         slug="simulations",