feat: add configurable max hashtag limit filter for spam prevention

Adds a security setting to hide posts with more than X hashtags (t tags),
defaulting to 5. Applied at the feed filter level via FilterByListParams.match()
and Account.isAcceptable() to cover all feeds. Configurable in Security Filters
settings, with 0 to disable.

https://claude.ai/code/session_01NMVypgGSU9EjQA7hZ9uvjD

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip01Core/tags/hashtags/EventExt.kt

@@ -24,6 +24,8 @@ import com.vitorpamplona.quartz.nip01Core.core.Event
 
 fun Event.anyHashTag(onEach: (str: String) -> Boolean) = tags.anyHashTag(onEach)
 
+fun Event.countHashtags() = tags.countHashtags()
+
 fun Event.hasHashtags() = tags.hasHashtags()
 
 fun Event.hashtags() = tags.hashtags()