feat(billing): add usage analytics charts and summary totals

Add daily usage trend charts with multi-metric toggles, overview vs user
analysis views, date-range filtering, and usage summary API for interval
and all-time totals.

Co-authored-by: Cursor <cursoragent@cursor.com>

package.json

@@ -29,6 +29,7 @@
     "react": "^19.0.0",
     "react-dom": "^19.0.0",
     "react-router-dom": "^7.13.1",
+    "recharts": "^3.10.1",
     "redis": "^4.7.1",
     "sharp": "0.35.2",
     "undici": "^6.26.0"