[Contract] Bounty Category Metadata Enums

[gabito1451]

Independence Note: Define the Enum without needing mapping to real bounty objects yet.

Context:
Bounties should have structured categories for machine-readability on-chain.

Objective:
Implement a Category Enum within the contract types.

Acceptance Criteria:

• Define enum BountyCategory { Development, Design, Documentation, Research, Other }.
• Ensure it supports serialization for Soroban types.
• Add a category field to the Bounty struct.
• Write a test that initializes a bounty with a specific category and verifies it is stored correctly.

Technical Pointers:

• Enums are far more gas-efficient than storing the Full Category name as a String.

[ericjoye]

Understand the need for an on-chain enum to optimize storage and gas costs over strings. I'll add the BountyCategory enum, include it in the Bounty struct, ensure Soroban serialization, and write a test verifying category persistence. Years of Rust/Stellar development. Open to a PR with fixed-price; hourly also possible if needed.

[zp6]

PR submitted: #1 (zp6#1). Wallet: zp6