Add More Granular Notification Settings

[fwag]

Feature Description

Is your feature request related to a problem? Please describe.
Currently, Gitea’s notification system offers a very broad enable/disable toggle, which can lead to either being overwhelmed with notifications or missing important updates. Users are often flooded with updates for issues and PRs they're not directly involved in, making it difficult to track relevant activity.

Describe the solution you'd like
It would be really helpful to implement more granular notification settings, allowing users to subscribe only to specific types of events. For example:

Notify only when:

• I'm mentioned (@username) in a comment or description

  • I'm assigned to an issue or PR
  • I'm requested as a reviewer
  • I'm subscribed manually
  • Someone replies to a comment I made

• Watch / Ignore repository options, similar to GitHub:

  • Watching: You receive notifications for all conversations
  • Not watching: You only receive notifications when participating or mentioned
  • Ignore: You don’t receive any notifications

• Per-repository and per-thread notification control

These options would greatly reduce unwanted noise while still keeping users informed of relevant activity.

Describe alternatives you’ve considered
Right now, the only real workaround is to disable notifications entirely and manually check repositories, but this breaks the purpose of having notifications and leads to missed responsibilities (e.g., review requests).

Additional context
GitHub provides a good example of this functionality. Users can:

• Customize notifications per repository
• Choose to be notified only when participating or mentioned
• Adjust delivery settings (email, web, mobile)

Adding similar capabilities to Gitea would greatly improve user experience, especially for organizations with many contributors or large projects.

Screenshots

No response