Fix usage logging dedupe and reduce stats churn

- batch console log buffer events and support batched SSE log messages
- debounce usage stats update/pending events to reduce UI/runtime churn
- avoid awaiting request-success bookkeeping before returning provider responses
- deduplicate identical usage writes in usageHistory/daily aggregates
- reduce default logger verbosity from DEBUG to INFO (overridable via LOG_LEVEL)

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

src/app/(dashboard)/dashboard/console-log/ConsoleLogClient.js

@@ -47,6 +47,11 @@ export default function ConsoleLogClient() {
           const next = [...prev, msg.line];
           return next.length > CONSOLE_LOG_CONFIG.maxLines ? next.slice(-CONSOLE_LOG_CONFIG.maxLines) : next;
         });
+      } else if (msg.type === "lines") {
+        setLogs((prev) => {
+          const next = [...prev, ...msg.lines];
+          return next.length > CONSOLE_LOG_CONFIG.maxLines ? next.slice(-CONSOLE_LOG_CONFIG.maxLines) : next;
+        });
       } else if (msg.type === "clear") {
         setLogs([]);
       }