milestones::release_issue panics (not a typed error) if Treasury is missing — require_treasury().unwrap()

Problem

Same pattern as escrow: release_issue uses require_treasury::<DataKey>(&env).unwrap().

Return Error::NotInitialized instead.

Related: #7

Addressed in PR #627.

Replaced require_treasury::<DataKey>(&env).unwrap() with require_treasury::<DataKey>(&env).ok_or(Error::NotInitialized)? in milestones::release_issue, eliminating the unhandled host panic.
Added unit test test_release_issue_returns_not_initialized_if_treasury_missing verifying Err(Ok(Error::NotInitialized)) is cleanly returned.
100% test pass rate across mergefi-milestones (60 tests passed) and 0 Clippy warnings.

Bounty Payout Address (Base USDC): 0xfE777c43e4B0A24fFA1527eD520d1E7f9ECED483