The ix_project_tasks_parent_task_id index already existed on the
production DB, causing migration 057 to fail with DuplicateTableError.
Switched all CREATE INDEX statements to raw SQL with IF NOT EXISTS.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Enables multi-user project collaboration mirroring the shared calendar
pattern. Includes ProjectMember model with permission levels, task
assignment with auto-membership, optimistic locking, field allowlist
for assignees, disconnect cascade, delta polling for projects and
calendars, and full frontend integration with share sheet, assignment
picker, permission gating, and notification handling.
Migrations: 057 (indexes + version + comment user_id), 058
(project_members), 059 (project_task_assignments)
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
