Add "Select all read-only scopes" option on PAT creation screen

[stilla]

When customers need to share a personal access token (PAT) with support, they currently have to be told which individual scopes to select one by one. Many customers are comfortable just granting all read-only scopes, but there's no quick way to do that.

Proposed Solution

Add a "Select all read-only scopes" option (e.g. a toggle or checkbox) on the OAT creation/configuration screen that pre-selects all available read-only scopes in one click.

This reduces friction for customers and simplifies the support handoff process.

_{Sent by @rishi-raj-jain from Feature request: Pre-select read-only scopes.}