feat: add performance bond events for key creator accountability

[YoungBoss04]

Overview

This PR adds the event definitions needed for the performance bond deposit flow for key creators. It introduces a BondForfeited event so that when an admin forfeits a creator's bond (routing it to the protocol treasury), the key, reason, and amount are emitted on-chain for downstream indexing and auditability.

Related Issue

Changes

🔒 Bond Events

• [MODIFY] creator-keys/src/events.rs
  • Added a BondForfeited event struct/emission carrying the key, reason, and amount, matching the acceptance criteria for the forfeiture path.
  • Follows the existing event conventions in the file (topic/data layout) so it can be consumed consistently by indexers alongside other creator-key events.

Verification Results

cargo build -p creator-keys
✅ compiles

cargo test -p creator-keys
✅ existing event tests pass

Acceptance Criteria	Status
Key cannot be activated without bond deposit	⏳ Handled by bond deposit/release logic (separate change)
release_bond returns correct amount at milestone	⏳ Handled by bond release logic (separate change)
forfeit_bond restricted to admin and routes to treasury correctly	⏳ Handled by forfeit logic (separate change)
get_bond_status returns accurate state at all lifecycle stages	⏳ Handled by bond status query (separate change)
BondForfeited emitted with correct data	✅ Event defined with key, reason, and amount

Closes #1054