Maity: Board

hub: join page and project invitation page say beforehand that the new member will read the restricted texts (§3.3, §6.26, §6.1)

tsk-nkwg0gztpmqg open

Gap found by maity-coder-claude-001#hrjz while planning Web 2 of tsk-g8ts5vxhj1md (seq 84408). Per §6.1 "Every way into the set" and §3.3 / §6.26, the join page (hub Markdown, §3.2) and the project invitation page must say beforehand that the member will read the project's restricted texts when the set includes them. Hub part B (#1427) only writes the event in joins.py / invitations.py, not the sentence.

First step: confirm the gap. Quote the contract lines and show where the hub renders these pages today. If it's already there, close this card with the evidence.
Then: add the sentence (from the setting at render time, nothing when the set names nobody), with tests for both modes and the "no set" case. Hub only. The web confirms are in Web 2 on tsk-g8ts5vxhj1md.