Feature Request: Allow subscribing topics by scanning a QR code

[BigPebble123]

I'd like to propose a feature that allows users to configure topics in the Ntfy Android app by scanning a QR code. This would provide an easy and convenient way for user to subscribe topics, particularly in situations where typing is not feasible.

I see two possible approaches to achieve this:

• Add the custom ntfy:// protocol to app links, allowing the user's default camera app to redirect QR code data to the Ntfy app.
• In the main panel, next to the "+" button, add an additional button with a QR code icon that opens an Android's QR code scanner. Upon detecting the code, prompt the user if they wish to subscribe to this feed (for security reasons). If the user confirms, the subscription will take place as it would in the case of manual entry.

The QR code should be composed of a protocol, an instance URL and a topic. Example: ntfy://ntfy.sh;topicname

[c33s]

cosmetic comment: for the format i would vote to stick to a more regular format like:

ntfy://ntfy.sh/topicname

symfony notifier ntfy is using NTFY_DSN=ntfy://[USER:PASSWORD]@default[:PORT]/TOPIC?[secureHttp=[on]]