docs: flip FoF section 20a badges to v0.7.0 + sessions.md release entry
design.html section 20a (Friend-of-Friend Visibility):
- Section header badge: planned → v0.7.0 complete
- FoFClosed PostVisibility table row: planned → v0.7.0
- All 5 layer rows in the implementation table: planned → v0.7.0
- Custom-subset row retained as v2 (genuinely deferred per spec)
sessions.md: full session entry for the Layer 1-5 implementation arc.
34 commits, ~24 new fof:: integration tests, key design decisions
preserved (slot_binder_nonce circularity fix, per-post pub_x/priv_x,
multi-epoch receiver-chain V_me storage, retroactive cascade delete,
key-burn semantics).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
ad9282f24a