#29 wiki: human list size column + schema H1-fallback doc

SOURCE: swarm friction #3+#8 (verified: wiki list --json HAS size; human table omits it; schema says index title = first H1, H1-less pages fall back to filename — undocumented). FIX: human wiki list gains a size column (thin view aligned with json path,title,size); schema [wiki] documents: "index title = first H1, else filename". JSON unchanged. DONE: human shows size; schema states fallback.