Implement Provisioning List management

[dfederm]

A SmartStart-enabled controller maintains a Provisioning List - an in-memory collection of devices expected to join the network, keyed by DSK. Each entry contains the DSK, requested security classes, bootstrapping mode, inclusion status, and optional product metadata.

Scope:

• ProvisioningList class in ZWave project:
  • Add(ProvisioningEntry) / Remove(DSK) / Get(DSK) / GetAll()
  • ProvisioningEntry record: DSK, requested security classes, bootstrapping mode (SmartStart / S2 only / ZWLR SmartStart), inclusion status (Pending / Active / Inactive / Included), product type/ID, name, location
  • Lookup by NWI HomeID (for matching incoming SmartStart Prime commands)
  • Thread-safe for concurrent access
• Persistence interface: IProvisioningListStore with a file-backed default implementation (JSON or similar) - the list must survive restarts
• Expose on Controller: Controller.ProvisioningList property
• Public API: Controller.ProvisionSmartStartNode(entry), Controller.UnprovisionSmartStartNode(dsk)
• Events: ProvisioningEntryAdded, ProvisioningEntryRemoved, ProvisioningEntryStatusChanged

Design notes: A dedicated class with IProvisioningListStore for persistence is clean - it separates concerns and makes the
list testable without a full driver.

Depends on: #157 (DSK utilities)