feat: add services page and API endpoints for service cost breakdown

- Implemented new API endpoints for fetching global services and service tenants details.
- Created a new services.html page with a sidebar for navigation and a chart for service costs.
- Updated frontend JavaScript to handle service data loading and rendering.
- Enhanced the dashboard with provider filtering options for AWS and Azure.
- Added a segmented toggle for selecting the date range for service costs.
- Improved styling for the sidebar and data tables.
- Refactored common utility functions for better reusability across pages.

frontend/static/tenant.js

@@ -68,12 +68,13 @@ function renderKpis(data) {
   if (isMonthly) {
     document.getElementById("kpi-current-label").textContent = `Total — ${p.months.length} derniers mois`;
   } else {
-    document.getElementById("kpi-current-label").textContent = `Total — ${p.range_days} derniers jours`;
+    document.getElementById("kpi-current-label").textContent = `Total — ${rangeLabel(p.range_days)}`;
   }
   document.getElementById("kpi-current").textContent = formatEUR(p.current_total);
 
   if (!isMonthly) {
-    document.getElementById("kpi-previous-label").textContent = `Total — ${p.range_days} jours précédents`;
+    document.getElementById("kpi-previous-label").textContent =
+      p.range_days === 1 ? "Total — veille" : `Total — ${p.range_days} jours précédents`;
     document.getElementById("kpi-previous").textContent = p.has_previous ? formatEUR(p.previous_total) : "—";
 
     const deltaEl = document.getElementById("kpi-delta");
@@ -99,7 +100,7 @@ function renderDailyChart(data) {
 
   document.getElementById("daily-chart-title").textContent = isMonthly
     ? `Coûts mensuels — ${p.months.length} derniers mois`
-    : `Coûts journaliers — ${p.range_days} derniers jours`;
+    : `Coûts journaliers — ${rangeLabel(p.range_days)}`;
 
   if (dailyChart) {
     dailyChart.destroy();