[ dergigi/boris ] fix: resolve React Hooks violation in NostrMentionLink component

- Move useEventModel hook call to top level (Rules of Hooks)

- Extract pubkey before calling the hook

- Profile resolution now works correctly for npub and nprofile mentions

- Fixes issue where profiles weren't being fetched and displayed

https://github.com/dergigi/boris/commit/627ffd6c5d1b4a772572da07962f14b35b7b26fe