feat: add scenarios list page with metrics and quick actions

- Introduced a new template for listing scenarios associated with a project.
- Added metrics for total, active, draft, and archived scenarios.
- Implemented quick actions for creating new scenarios and reviewing project overview.
- Enhanced navigation with breadcrumbs for better user experience.

refactor: update Opex and Profitability templates for consistency

- Changed titles and button labels for clarity in Opex and Profitability templates.
- Updated form IDs and action URLs for better alignment with new naming conventions.
- Improved navigation links to include scenario and project overviews.

test: add integration tests for Opex calculations

- Created new tests for Opex calculation HTML and JSON flows.
- Validated successful calculations and ensured correct data persistence.
- Implemented tests for currency mismatch and unsupported frequency scenarios.

test: enhance project and scenario route tests

- Added tests to verify scenario list rendering and calculator shortcuts.
- Ensured scenario detail pages link back to the portfolio correctly.
- Validated project detail pages show associated scenarios accurately.

routes/navigation.py

@@ -0,0 +1,63 @@
+from __future__ import annotations
+
+from datetime import datetime, timezone
+
+from fastapi import APIRouter, Depends, Request
+
+from dependencies import (
+    get_auth_session,
+    get_navigation_service,
+    require_authenticated_user,
+)
+from models import User
+from schemas.navigation import (
+    NavigationGroupSchema,
+    NavigationLinkSchema,
+    NavigationSidebarResponse,
+)
+from services.navigation import NavigationGroupDTO, NavigationLinkDTO, NavigationService
+from services.session import AuthSession
+
+router = APIRouter(prefix="/navigation", tags=["Navigation"])
+
+
+def _to_link_schema(dto: NavigationLinkDTO) -> NavigationLinkSchema:
+    return NavigationLinkSchema(
+        id=dto.id,
+        label=dto.label,
+        href=dto.href,
+        match_prefix=dto.match_prefix,
+        icon=dto.icon,
+        tooltip=dto.tooltip,
+        is_external=dto.is_external,
+        children=[_to_link_schema(child) for child in dto.children],
+    )
+
+
+def _to_group_schema(dto: NavigationGroupDTO) -> NavigationGroupSchema:
+    return NavigationGroupSchema(
+        id=dto.id,
+        label=dto.label,
+        icon=dto.icon,
+        tooltip=dto.tooltip,
+        links=[_to_link_schema(link) for link in dto.links],
+    )
+
+
+@router.get(
+    "/sidebar",
+    response_model=NavigationSidebarResponse,
+    name="navigation.sidebar",
+)
+async def get_sidebar_navigation(
+    request: Request,
+    _: User = Depends(require_authenticated_user),
+    session: AuthSession = Depends(get_auth_session),
+    service: NavigationService = Depends(get_navigation_service),
+) -> NavigationSidebarResponse:
+    dto = service.build_sidebar(session=session, request=request)
+    return NavigationSidebarResponse(
+        groups=[_to_group_schema(group) for group in dto.groups],
+        roles=list(dto.roles),
+        generated_at=datetime.now(tz=timezone.utc),
+    )