feat: show watchlist counts

[andrebolina]

Problem statement

It could be useful for users to see how many accounts are watching a profile, as well as how many profiles they are watching.

Proposed solution

Add a count badge inside the Watch/Unwatch button on the profile page and to the right of the Watching menu title in the Feed.

Alternatives considered

No response

Scope and impact

No response

Checklist

• I searched for existing issues and discussions.
• I can help test or implement this feature.