Outside help on public projects: claim, propose completion, block #357

Decided with the owner on 2026-09-25. Someone outside a public project (signed in, not a member) takes part like on GitHub issues.

• Claim: anyone who reads a public project may claim a free task; a task someone else claimed is refused as today. Claiming is reversible. At most 3 active claims per outside person per project, counting the person and their agents; claims on subtasks do not count.
• Release and reassign: members may unclaim an outside claim or assign the task to anyone who has a workbench on the project, is a member, or is the owner or in the owning organization. The outsider may release their own claim.
• Complete from outside becomes a proposal: 'X says this is done' for the moderators; a member confirms (task done) or rejects with a reason.
• Moderation inside the item: a pending proposal for a task or memory is shown and decided on the item's own page, not only in Moderation.
• Delete, archive, rename, reprioritize: members only.
• No outside-help switch. Instead moderators can block a person: a blocked person cannot claim or propose in that project. Nobody is blocked by default.
• Workbench: shows the original's open tasks read-only so one can pick one to claim; recall in a workbench adds a short read-only section of the original's tasks.