Removing then re-adding an issue to a cycle throws a unique-violation 500

[cavidelizade]

Summary

Removing an issue from a cycle and then adding it back throws a 500 and the issue can never be re-added to that cycle.

Where

CycleIssue has a gorm.DeletedAt so RemoveCycleIssue (apps/api/internal/store/cycle.go) is a soft delete, but cycle_issues has a plain UNIQUE (cycle_id, issue_id) that ignores deleted_at (migration 000001). AddCycleIssue does a plain Create.

Repro

1. Add issue X to cycle C.
2. Remove X from C (row is soft-deleted, physical row survives).
3. Add X to C again. The INSERT collides with the surviving row, Postgres returns a unique violation, the request 500s.

X can now never be re-added to C. The same failure hits CompleteCycle's transfer of incomplete issues when the target cycle previously held that issue.

Note

The codebase already handles this correctly elsewhere. PageStore.MoveTreeToProject hard-deletes project_pages for exactly this reason, and the workspace/project member upserts revive with Unscoped(). Cycle issues were missed. Every other join table (issue_assignees, issue_labels, module_issues, etc.) has no DeletedAt and hard-deletes, so they're fine.

Fix

Hard-delete cycle links, or upsert-revive the soft-deleted row, or make the constraint partial (WHERE deleted_at IS NULL).