Fix: deposit event not emitted when match transitions to Active state

[yahia008]

Priority: Low
Estimated Time: 30 minutes

Description:
When the second player deposits and the match transitions from Pending to Active, no match_activated event is emitted. Frontends cannot detect when a match is ready to start without polling get_match.

Tasks:

• Emit a ("match", "activated") event inside deposit when m.state transitions to Active
• Include match_id in event data
• Add test asserting the event is emitted only on the second deposit

[Itodo-S]

@Itodo-S has applied to work on this issue as part of the Stellar Wave Program's 3rd wave.

Please let me work on this issue; I can handle it.

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Itodo-S to this issue.

[techisigu]

@techisigu has applied to work on this issue as part of the Stellar Wave Program's 3rd wave.

I’m a smart contract developer who turns complex ideas into secure, production-ready blockchain code.
With strong skills in Rust and Solidity, I build systems that are fast, safe, and built to last.
My experience with the Stellar SDK lets me ship real-world Web3 solutions that actually move value

ℹ️ Repo Maintainers: To accept this application, review their application or assign @techisigu to this issue.