Updates the API and UI to allow users to add optional descriptions to time entries, with a visual indicator for cells containing descriptions. Replit-Commit-Author: Agent Replit-Commit-Session-Id: 55837015-10e9-4be9-b857-7f5e6be73772 Replit-Commit-Checkpoint-Type: full_checkpoint Replit-Commit-Event-Id: 3bc0faf3-6f86-46e5-8577-13a2e2e88062 Replit-Commit-Screenshot-Url: https://storage.googleapis.com/screenshot-production-us-central1/1cc377db-7ea0-49f2-97ce-c3e87e0228cc/55837015-10e9-4be9-b857-7f5e6be73772/Dzp7voC Replit-Helium-Checkpoint-Created: true