Previously isAgeRestrictedMessage() early-returned in messageCreate/messageUpdate,
so NSFW-channel messages were never stored at all. Now they are captured like
any message (visible in dashboard), while the existing age-restricted skip path
(queueMessageAnalysis -> buildAgeRestrictedSkipResult) marks them clean with flag
age_restricted WITHOUT calling the LLM.
NSFW content is also deliberately kept OUT of the Qdrant public semantic-search
archive (archiveMessageEmbedded skips when isAgeRestricted), so it can't be found
via public web search. No schema change needed (metadata already carries channel.nsfw).