# S006 — spaces backend (member-only)

The dogfood ACL primitive: one space whose member list decides who may
read and write. Everything private in 林集 hangs off this.

## What landed

- **zds fork fixes**: policy-gated writes/reads for space collections,
  local signing-key resolution, credential ceremony exercised in the zds
  smoke scripts.
- **app0 `core/spaces.zig`**: space create/add-member/remove-member/
  members; posts and reads scoped to a space (`post/read --space`).
- **CLI**: `linji space create --skey <s>`, `space add-member --space
  <uri> --did <did>`, `space remove-member`, `space members`.

## Key design fact

"Authority repo" threads/records are impossible as recorded: space
records live in **member repos** (`space.createRecord` with
repo=caller) — nobody can write to the community's repo. Member-repo
records with AT-URI refs became the standing pattern for everything
after (threads in S007, edits in S008).

## Verification

`zig build scenario-space` — 29 checkpoints, PASS; M001 scenario still
green (later retired by S007).