Added Sentry + mentions with @ + general fixes

We now have Sentry thanks to @egelhaus.
This allows us to fix many features.

• Added mentions: now in Bluesky, X, and LinkedIn, you can start typing "@" to get mentions.
• General fixed thanks to sentry
• Queries improvements (added indexes)

What's Changed

• Sentry by @nevo-david in #905
• Better mentioning functionality by @nevo-david in #911

Full Changelog: v2.0.8...v2.1.0