Fix Kiro token refresh logic

src/lib/usageDb.js

@@ -228,6 +228,13 @@ export async function appendRequestLog({ model, provider, connectionId, tokens,
     const line = `${timestamp} | ${m} | ${p} | ${account} | ${sent} | ${received} | ${status}\n`;
 
     fs.appendFileSync(LOG_FILE, line);
+
+    // Trim to keep only last 200 lines
+    const content = fs.readFileSync(LOG_FILE, "utf-8");
+    const lines = content.trim().split("\n");
+    if (lines.length > 200) {
+      fs.writeFileSync(LOG_FILE, lines.slice(-200).join("\n") + "\n");
+    }
   } catch (error) {
     console.error("Failed to append to log.txt:", error.message);
   }