Workspaces (multi-user accounts)

[Yentec]

Context

The current model is single-user: a User owns links and keys directly. Real-world usage (agencies, teams) requires shared ownership.

Goal

Introduce Workspace as the ownership boundary. A user belongs to one or more workspaces with a role (owner, member).

Approach (high-level)

• New tables: Workspace, WorkspaceMember(userId, workspaceId, role).
• Link.userId -> Link.workspaceId. Migration with a default workspace per existing user.
• JWT payload gains a workspaceId (active workspace).
• POST /v1/workspaces, POST /v1/workspaces/:id/invitations, GET /v1/workspaces.
• API keys get scoped to a workspace.

Acceptance criteria

• Data model migrated with zero data loss
• All /v1/links* endpoints scoped by workspace
• Invitation flow (email + token) — email sending is optional, token returned in API response is enough for v1
• Migration tested with seed data

Notes

This is a significant change. Likely split into 3-4 PRs: data model, scoping, invitations, API keys.