Consider deduping/sorting meili results

[almostSouji]

Meili multi search returns queries for each scope, which are currently concatenated with a simple flatmap - if a prior scope has enough (potentially bad) matches, they will currently be prioritized over better fitting candidates in later scopes. additionally discord.js re-exports structures (for example builders), resulting in duplicates

• consider deduping results (prioritize source over re-exported scopes (aka: no discord.js))
• consider filling the AC results in a round-robin approach rather than flatmapping the hits

Derived from #235 (comment)