fix bugss and adoption lifecycle

[samad13]

PR: Pet Status Lifecycle Implementation (Closes #17)

Overview

This PR implements the Pet Status Lifecycle feature, enforcing a state machine for pet status transitions throughout the adoption and custody process. It ensures that pets can only move between valid states, maintaining data integrity and preventing invalid transitions.

Features

• State Machine for Pet Status:
  • Enforces valid transitions: AVAILABLE → PENDING → ADOPTED, AVAILABLE → IN_CUSTODY → AVAILABLE, etc.
  • Blocks invalid transitions (e.g., ADOPTED → PENDING, IN_CUSTODY → ADOPTED).
  • Allows admin override for ADOPTED → AVAILABLE (return scenario).
• Transition Validation:
  • Centralized validator for all status changes.
  • Throws clear errors for invalid transitions.
  • Logs all status changes for audit trail.
• API Endpoints:
  • PATCH /pets/:id/status: Update pet status with validation and audit logging.
  • GET /pets/:id/transitions: Get allowed transitions and current status for a pet.
  • GET /pets/:id/transitions/allowed: Get allowed transitions for the current user (role-aware).
• Swagger Documentation:
  • All endpoints are fully documented and visible in Swagger UI.
  • Request/response schemas and examples included.
• Test Coverage:
  • Unit tests for all valid and invalid transitions.
  • Tests for admin overrides and edge cases.

Acceptance Criteria

• Valid transitions work as expected.
• Invalid transitions are blocked with clear error messages.
• Admin can override certain restrictions.
• Status changes are logged.
• All endpoints are documented in Swagger.
• Unit tests cover all scenarios.

Closes #106

---

Please review the implementation and test the endpoints via Swagger UI (/api/docs).