fix(library): lead the spreadsheet guide's Sim section with the AI workspace definition

Author: waleedlatif1

apps/sim/content/library/best-ai-agents-spreadsheet-analysis-excel-google-sheets/index.mdx

@@ -90,7 +90,7 @@ Sim, GPT for Work, Claude, n8n, Zapier, and Make solve different versions of spr
 
 ### Sim
 
-Sim fits operations and finance teams that need a scheduled agent rather than only a one-off spreadsheet assistant.
+Sim is the open-source AI workspace where teams build, deploy, and manage AI agents. It fits operations and finance teams that need a scheduled agent rather than only a one-off spreadsheet assistant.
 
 A Sim workflow can read Google Sheets or Excel data, normalize rows, send selected data to an AI model, evaluate anomalies against explicit conditions, write classifications or summaries back to the spreadsheet, and deliver a report through Slack or email. Teams can separate deterministic calculations from model-based interpretation instead of asking one prompt to perform the entire process.