firebase/functions-samples ? reverse-engineered prompt

Build me a repo of runnable Cloud Functions for Firebase samples, like a little library of examples that show the most common things people do with Firebase functions.

I want a clear README that explains each sample in simple terms and makes it easy to find the right one, including examples for Firestore, Realtime Database, Storage uploads, Auth events, HTTPS requests, callable functions, Pub/Sub, alerts, and a few image handling examples. It should feel like a real set of copy and pasteable quickstarts, not just stub files.

Please make the examples work for the supported runtimes in the project, and keep the code easy to read so someone learning Firebase can understand what each function is doing. If you need to check current Firebase docs or best practices, look them up online.

Also include a few testing examples and keep the structure organized so it’s obvious which sample belongs to which trigger.