Approve a submitted time entry

POST /time-entries/:id/approve

Approving locks the entry: its status becomes locked (not approved) and approvedAt and lockedAt are set.

Permission: write:time_entry. The key must be bound to a user whose role is manager or admin.

Add-on: requires the Illumera add-on. Without it the call returns 403 with reason: addon_required.

Plan: requires time tracking. When it is off the call returns 402 with reason: feature_disabled.

/time-entries/:id/approve