Feat/status

[nafsonig]

I've successfully implemented explicit status enums and state transition validation for the campaign contract. Here's what was done:

1. Updated Status Enums in types.rs

CampaignStatus - 4 states with explicit transitions:

• Active - Campaign accepting donations
• GoalReached - Goal reached, still accepting donations until deadline
• Ended - Deadline passed or campaign concluded
• Cancelled - Campaign cancelled by creator (terminal state)

MilestoneStatus - 3 states with explicit transitions:

• Locked - Milestone condition not yet met
• Unlocked - Target amount reached, awaiting release
• Released - Funds released to beneficiary (terminal state)

2. Added Comprehensive Error Codes in types.rs

New error variants for state transition validation:

• InvalidCampaignTransition - Campaign status transition not allowed
• InvalidMilestoneTransition - Milestone status transition not allowed
• CampaignNotActive - Campaign must be Active to accept donations
• CampaignEnded - Campaign end_time has passed
• GoalNotReached - Cannot transition to GoalReached before reaching goal

3. Implemented State Transition Validators in lib.rs

validate_campaign_transition() enforces:

Active → GoalReached, Ended, or Cancelled ✓
GoalReached → Ended or Cancelled ✓
Ended → Cancelled only ✓
Cancelled → terminal (no transitions) ✓

validate_milestone_transition() enforces:

Locked → Unlocked or Released ✓
Unlocked → Released only ✓
Released → terminal (no transitions) ✓
Prevents backwards transitions (Unlocked → Locked) ✓

4. Enhanced Error Handling

• panic_with_error() function handles all 10+ error codes with descriptive symbols
• Each invalid transition panics with specific, auditable error message
• Transitions are explicit and auditable on-chain

All status enums implement #[contracttype] for Soroban serialization, and invalid transitions will panic with descriptive error codes as required.

Made changes.

closes #171

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You can now already apply to more issues while waiting for a review of this PR. Keep up the great work! 🚀

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[ayshadogo]

Thank you for the contribution