feat: add live Discord sharing functionality with dynamic habit progress images

- Implemented live card image generation for user habits using canvas.
- Created API endpoints for starting and managing live Discord sharing sessions.
- Added tests for live Discord sharing to ensure functionality and reliability.
- Introduced CSS styles for the live Discord sharing interface.
- Enhanced error handling and state management for Discord message updates.

scripts/dashboard-preview.ts

@@ -14,7 +14,7 @@ let sharedImage: Blob | null = null;
 let reminderMessage: string | null = null;
 const previewDiscord: DiscordFetch = async (url, init) => {
   if (url.endsWith("/users/@me/channels")) return Response.json({ id: "523456789012345678" });
-  if (init?.method === "POST") {
+  if (init?.method === "POST" || init?.method === "PATCH") {
     if (init.body instanceof FormData) sharedImage = init.body.get("files[0]") as Blob;
     else reminderMessage = JSON.parse(String(init.body)).content;
     return Response.json({ id: "423456789012345678" });