[SiteRelEnby]

Brings the system relationships feature to Android, matching web. Despite the name it is entirely intra-system: a private graph a user draws among their own members (and groups). No cross-system/federation, no request/accept flow, no external identity - the counterparty is always another member/group already in the account.

Two layers

Relationship types (Settings > System > Relationships) - a per-system vocabulary:

• Create / edit / delete, with a Kind: symmetric (one label, e.g. partner), directional (two labels, e.g. parent / child), or either (both, with an optional "mutual").
• Optional preset picker to prefill the form (partner, parent/child, protector, ...).
• Kind is immutable after creation (server-enforced) - the edit dialog says so.
• Delete cascades its edges; the confirm dialog warns.

Edges - a reusable RelationshipsEditor embedded on member and group screens:

• Add/remove relationships from a member or group's edit screen; the member/group profile shows them read-only.
• Pick the other party from a dropdown, and (for directional/either types) the direction or a mutual flag.
• Labels + direction are resolved server-side per viewpoint, so the client renders RelationshipFromViewpoint as-is (direction glyph + label: other name). No edit-in-place for edges (delete + recreate), matching the backend.

Notable details

• Payload builder (buildRelationshipEdge) mirrors web's handleAdd (source/target orientation for forward vs reverse, mutual normalisation for either) and is pure + unit-tested.
• New models in RelationshipModels.kt (string-typed enums per project convention) + a // Relationships group of 10 endpoints in SheafApiService.kt.
• Endpoints require token scopes relationships:read/write/delete; the main-app session token has them (web works). A 403 would be a backend/token concern.

Deferred (follow-up)

• The whole-system force-directed graph view (/relationships/graph) - a dedicated Compose-canvas PR.
• A Sheaf/OpenPlural import toggle for relationships (backend already exports/imports them).

Testing

• RelationshipEdgePayloadTest: symmetric, directional forward/reverse (source swap), either+mutual, either-directional, mutual-ignored-for-non-either, visibility always private.
• :app:assemblePlayRelease + :wear:assembleRelease green (through R8); unit suite green; em-dash clean.
• Not device-tested here; worth a pass: define a type of each Kind; add member relationships of each and confirm the label + direction glyph render from the viewpoint; toggle Mutual on an either type; remove one; repeat on a group; delete a type and confirm its edges vanish (cascade); confirm dup-name / duplicate-pair (409) surface a readable error.