feat: Enhance project and scenario creation with monitoring metrics

- Added monitoring metrics for project creation success and error handling in `ProjectRepository`.
- Implemented similar monitoring for scenario creation in `ScenarioRepository`.
- Refactored `run_monte_carlo` function in `simulation.py` to include timing and success/error metrics.
- Introduced new CSS styles for headers, alerts, and navigation buttons in `main.css` and `projects.css`.
- Created a new JavaScript file for navigation logic to handle chevron buttons.
- Updated HTML templates to include new navigation buttons and improved styling for buttons.
- Added tests for reporting service and routes to ensure proper functionality and access control.
- Removed unused imports and optimized existing test files for better clarity and performance.

routes/reports.py

@@ -1,6 +1,6 @@
 from __future__ import annotations
 
-from datetime import date
+from datetime import date, datetime
 from urllib.parse import urlencode
 
 from fastapi import APIRouter, Depends, HTTPException, Query, Request, status
@@ -12,7 +12,6 @@ from dependencies import (
     get_unit_of_work,
     require_any_role,
     require_project_resource,
-    require_roles,
     require_scenario_resource,
 )
 from models import Project, Scenario, User
@@ -30,6 +29,93 @@ from services.unit_of_work import UnitOfWork
 router = APIRouter(prefix="/reports", tags=["Reports"])
 templates = Jinja2Templates(directory="templates")
 
+# Add custom Jinja2 filters
+
+
+def format_datetime(value):
+    """Format a datetime object for display in templates."""
+    if not isinstance(value, datetime):
+        return ""
+    if value.tzinfo is None:
+        # Assume UTC if no timezone
+        from datetime import timezone
+        value = value.replace(tzinfo=timezone.utc)
+    # Format as readable date/time
+    return value.strftime("%Y-%m-%d %H:%M UTC")
+
+
+def currency_display(value, currency_code):
+    """Format a numeric value with currency symbol/code."""
+    if value is None:
+        return "—"
+
+    # Format the number
+    if isinstance(value, (int, float)):
+        formatted_value = f"{value:,.2f}"
+    else:
+        formatted_value = str(value)
+
+    # Add currency code
+    if currency_code:
+        return f"{currency_code} {formatted_value}"
+    return formatted_value
+
+
+def format_metric(value, metric_name, currency_code=None):
+    """Format metric values appropriately based on metric type."""
+    if value is None:
+        return "—"
+
+    # For currency-related metrics, use currency formatting
+    currency_metrics = {'npv', 'inflows', 'outflows',
+                        'net', 'total_inflows', 'total_outflows', 'total_net'}
+    if metric_name in currency_metrics and currency_code:
+        return currency_display(value, currency_code)
+
+    # For percentage metrics
+    percentage_metrics = {'irr', 'payback_period'}
+    if metric_name in percentage_metrics:
+        if isinstance(value, (int, float)):
+            return f"{value:.2f}%"
+        return f"{value}%"
+
+    # Default numeric formatting
+    if isinstance(value, (int, float)):
+        return f"{value:,.2f}"
+
+    return str(value)
+
+
+def percentage_display(value):
+    """Format a value as a percentage."""
+    if value is None:
+        return "—"
+
+    if isinstance(value, (int, float)):
+        return f"{value:.2f}%"
+
+    return f"{value}%"
+
+
+def period_display(value):
+    """Format a period value (like payback period)."""
+    if value is None:
+        return "—"
+
+    if isinstance(value, (int, float)):
+        if value == int(value):
+            return f"{int(value)} years"
+        return f"{value:.1f} years"
+
+    return str(value)
+
+
+templates.env.filters['format_datetime'] = format_datetime
+templates.env.filters['currency_display'] = currency_display
+templates.env.filters['format_metric'] = format_metric
+templates.env.filters['percentage_display'] = percentage_display
+templates.env.filters['period_display'] = period_display
+
 READ_ROLES = ("viewer", "analyst", "project_manager", "admin")
 MANAGE_ROLES = ("project_manager", "admin")
 
@@ -296,35 +382,9 @@ def project_summary_page(
     )
 
     service = ReportingService(uow)
-    report = service.project_summary(
-        project,
-        filters=scenario_filter,
-        include=include_options,
-        iterations=iterations or DEFAULT_ITERATIONS,
-        percentiles=percentile_values,
+    context = service.build_project_summary_context(
+        project, scenario_filter, include_options, iterations or DEFAULT_ITERATIONS, percentile_values, request
     )
-    context = {
-        "request": request,
-        "project": report["project"],
-        "scenario_count": report["scenario_count"],
-        "aggregates": report["aggregates"],
-        "scenarios": report["scenarios"],
-        "filters": report["filters"],
-        "include_options": include_options,
-        "iterations": iterations or DEFAULT_ITERATIONS,
-        "percentiles": percentile_values,
-        "title": f"Project Summary · {project.name}",
-        "subtitle": "Aggregated financial and simulation insights across scenarios.",
-        "actions": [
-            {
-                "href": request.url_for(
-                    "reports.project_summary",
-                    project_id=project.id,
-                ),
-                "label": "Download JSON",
-            }
-        ],
-    }
     return templates.TemplateResponse(
         request,
         "reports/project_summary.html",
@@ -399,40 +459,9 @@ def project_scenario_comparison_page(
         )
 
     service = ReportingService(uow)
-    report = service.scenario_comparison(
-        project,
-        scenarios,
-        include=include_options,
-        iterations=iterations or DEFAULT_ITERATIONS,
-        percentiles=percentile_values,
+    context = service.build_scenario_comparison_context(
+        project, scenarios, include_options, iterations or DEFAULT_ITERATIONS, percentile_values, request
     )
-    comparison_json_url = request.url_for(
-        "reports.project_scenario_comparison",
-        project_id=project.id,
-    )
-    comparison_query = urlencode(
-        [("scenario_ids", str(identifier)) for identifier in unique_ids]
-    )
-    if comparison_query:
-        comparison_json_url = f"{comparison_json_url}?{comparison_query}"
-
-    context = {
-        "request": request,
-        "project": report["project"],
-        "scenarios": report["scenarios"],
-        "comparison": report["comparison"],
-        "include_options": include_options,
-        "iterations": iterations or DEFAULT_ITERATIONS,
-        "percentiles": percentile_values,
-        "title": f"Scenario Comparison · {project.name}",
-        "subtitle": "Evaluate deterministic metrics and Monte Carlo trends side by side.",
-        "actions": [
-            {
-                "href": comparison_json_url,
-                "label": "Download JSON",
-            }
-        ],
-    }
     return templates.TemplateResponse(
         request,
         "reports/scenario_comparison.html",
@@ -478,33 +507,9 @@ def scenario_distribution_page(
         ) from exc
 
     service = ReportingService(uow)
-    report = service.scenario_distribution(
-        scenario,
-        include=include_options,
-        iterations=iterations or DEFAULT_ITERATIONS,
-        percentiles=percentile_values,
+    context = service.build_scenario_distribution_context(
+        scenario, include_options, iterations or DEFAULT_ITERATIONS, percentile_values, request
     )
-    context = {
-        "request": request,
-        "scenario": report["scenario"],
-        "summary": report["summary"],
-        "metrics": report["metrics"],
-        "monte_carlo": report["monte_carlo"],
-        "include_options": include_options,
-        "iterations": iterations or DEFAULT_ITERATIONS,
-        "percentiles": percentile_values,
-        "title": f"Scenario Distribution · {scenario.name}",
-        "subtitle": "Deterministic and simulated distributions for a single scenario.",
-        "actions": [
-            {
-                "href": request.url_for(
-                    "reports.scenario_distribution",
-                    scenario_id=scenario.id,
-                ),
-                "label": "Download JSON",
-            }
-        ],
-    }
     return templates.TemplateResponse(
         request,
         "reports/scenario_distribution.html",