EPIC: Sync, mobile and collaboration

Programme: #1

Own encrypted multi-device state, pairing/key recovery, explicit device authority, home/remote workers, shared workspaces and additional clients.

## Child issues
- [ ] #94 MESH-01 — Encrypted sync, pairing and key recovery
- [ ] #95 MESH-02 — Device authority and remote/home workers
- [ ] #96 MESH-03 — Shared workspaces and enterprise contexts
- [ ] #97 MESH-04 — Mobile and additional presentation clients

## Cross-cutting gates
Revoked devices lose future access, risky actions are single-authority/fenced across partitions, shared views never confer the union of collaborators' source rights, execution location/data flow is visible, and mobile does not inherit desktop-control assumptions.

Start by reading child issues #94–#97 to determine the scoped work for encrypted sync, device authority, shared workspaces, and additional clients. Use the cross-cutting gates as acceptance criteria: revoked devices lose future access, risky actions remain single-authority/fenced, shared views do not expand source rights, execution location and data flow are visible, and mobile avoids desktop-control assumptions.

Written by the indexing model from the issue text.