Add Test: non-admin cannot call unpause

**Priority:** High
**Estimated Time:** 15 minutes

**Description:**
`test_admin_pause_blocks_create_match` verifies pause works but there is no test confirming that a non-admin address cannot call `unpause()` to re-enable a paused contract.

**Tasks:**
- Admin calls `pause()`
- Call `unpause()` from a non-admin address
- Assert auth failure (panic or `Error::Unauthorized`)