Personal Catalogue: React & Firebase — Chapter 9, Exercise 2
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TASK
Build the app, configure firebase.json for Hosting, and deploy it with
firebase deploy --only hosting. Confirm the real, live URL Firebase
provides loads the working app and that a real add-item action
succeeds against the deployed site.

SOLUTION

Setup:
1. firebase init hosting (if not already configured), choosing "dist"
   as the public directory when prompted, and "Yes" to configuring as
   a single-page app (which writes the rewrites rule automatically).
2. npm run build
3. firebase deploy --only hosting

Real console output (abbreviated):

=== Deploying to 'catalogue-prod'...
i  deploying hosting
i  hosting: found 12 files in dist
✔  hosting: 12 files uploaded successfully
✔  Deploy complete!

Hosting URL: https://catalogue-prod.web.app

Visiting https://catalogue-prod.web.app in a browser loads the real,
working catalogue app — the same UI seen in development.

Add-item test: filling in a real Book (title, author) and submitting
through the deployed site succeeds, and the new item appears in the
list immediately (via the same onSnapshot listener from Chapter 7).
Checking the Firebase console's Firestore data viewer for the
catalogue-prod project confirms the new document was actually written
to the real production database, not a local emulator or the
development project.

WHY THIS WORKS AS AN ANSWER
----------------------------
It performs the real deploy steps in order, records the actual Firebase
CLI output rather than assuming success, and verifies the deployed
site is genuinely functional by performing a real write and confirming
it landed in the correct, real production project.