Add owner_id column to workspaces table and backfill existing
workspaces from membership data (TASK-410 + TASK-480).
- SQLite migration 030 and Postgres migration 010 add owner_id column
with indexes on (owner_id) and (owner_id, slug)
- Workspace, WorkspaceCreate models updated with OwnerID field
- All workspace SELECT queries include owner_id
- CreateWorkspace INSERT includes owner_id
- handleCreateWorkspace sets owner_id from authenticated user
- backfillWorkspaceOwners extended: sets owner_id using D3 logic
(earliest owner member → earliest member → first admin)
- TypeScript Workspace type updated
Global UNIQUE(slug) constraint preserved for now; will be replaced
with UNIQUE(owner_id, slug) in TASK-412 when auth-scoped resolution
needs it.
xarmian
520a7ca27b