Phase 1c: DiscoveredPeripheral.peripheral sugar + manager stamp

[itsniper]

Parent: #50

Requirements

• Each DiscoveredPeripheral is stamped with its vending ReliaBLEManager (or equivalent) so .peripheral resolves on the correct registry (multi-manager safe).
• discovered.peripheral returns the interned handle (same instance/identity as registry), not a fresh object per ad.

Acceptance criteria

• Sugar works for manager-vended discoveries
• Repeated ads for same device resolve to same handle
• Documented in DocC