Social Creative Builder Turns one approved idea into N platform-native, ready-to-paste packages — post/thread, caption, Threads text, 小红书 note, link post with first-comment placement — plus a carousel slide-spec mode. It is the per-post build skill of the ECHO Craft phase and feeds the C sub-items directly: claim-ledger match and required disclosures (the upstream of the ECHO C1/C2 vetoes), dated-norm-card adaptation (never verbatim cross-posting), hook/payload match with cited format specs, the accessibility pack, and link + first-comment placement — see echo-benchmark.md. Claims handling mi…