Infinite Loading When Text & Doc URL Are Both Empty on Input Page

On the Text Input page (both Web and Extension), if the user does not enter any text and does not provide a Doc URL, the app enters a loading state that never ends.

This happens because the case where both inputs are empty is not handled. Ideally, in this scenario, the app should:

- Prevent the loading state from starting
- Show an alert/message asking the user to add some content (either text or a Doc URL)

### Steps to Reproduce:

Open the Text Input page (Web or Extension)
Leave the text field empty
Leave the Doc URL field empty
Click the Next button

### Expected Behavior:

The app should not start loading
A clear alert or validation message should appear, e.g.
“Please enter some text or provide a document URL.”

### Actual Behavior:

The app enters a loading state
The loading never ends
No feedback is shown to the user

### Impact:

Confusing user experience
Makes the app feel broken or unresponsive
User has no indication of what went wrong

### Proposed Fix:

Add a validation check before starting the process:
- If both text and docUrl are empty:
- Show an alert / error message
- Do not trigger the loading state
- Do not proceed with the request