MEDIUM: Missing placement approval workflow documentation

[Joshkovu]

Severity: MEDIUM

Issue Description

Multiple status transition endpoints exist but workflow is undocumented:

• No clear state machine definition
• Transitions not validated (e.g., can move from completed back to draft)
• PlacementStatusHistory exists but unclear usage
• Edge cases not handled

Location

• \logify-backend/apps/placements/views.py\
• \logify-backend/apps/placements/models.py\

Suggested Solution

1. Document placement state machine with diagram
2. Define valid transitions (e.g., draft→submitted→approved→started→completed)
3. Add transition validation in update_status endpoint
4. Prevent invalid backwards transitions
5. Add PlacementStatusHistory tracking for audit trail
6. Test all state transitions

Estimated Effort: 3 hours