hub-resident cross-project WI board: add cross_wi table + MCP wi_add/wi_close/wi_ls/wi_show/wi_event tools. Replaces per-host bwi for cross-project items (mars/pluto/venus/evolutiva). 3-PM consensus pm-mars-29395 / pluto-29405 / venus-29411; Elazar greenlight elazar-…-29506 Q2. Owner: llmmsg-srv-cc-w.