rename communityEcology → board across backend

Model, schemas, API routes, activity log, and all server handlers
updated. Old ecology/ and community-ecology routes removed, new
board/ routes added. Tests updated and new board-suggestions tests
written (10 cases).

server/api/onboarding/track.post.js

@@ -32,10 +32,10 @@ export default defineEventHandler(async (event) => {
       _id: member._id,
       'onboarding.completedAt': null,
       'onboarding.eventPageVisited': true,
-      'onboarding.ecologyPageVisited': true,
+      'onboarding.boardPageVisited': true,
       'onboarding.wikiClicked': true,
       'craftTags.0': { $exists: true },
-      'communityEcology.topics': {
+      'board.topics': {
         $elemMatch: { state: { $in: ['help', 'interested', 'seeking'] } },
       },
     },