Restack runtime data migration around signed API and semantic storage

[bytemaster-0xff]

Restacks the Runtime Data migration plan around the architecture now being implemented.

Key decisions:

• Runtime -> cloud uses the existing RuntimeSignedHttpClient signed HTTP path.
• LagoVista.IoT.RuntimeData lives in nuviot/appsupport and is hosted by the existing nuviot/nuviot API server.
• No RuntimeData lease, separate RuntimeData host, or new runtime-to-cloud RPC transport in V1.
• Existing DeploymentManagement/DeviceManagement DI and repos are reused by default.
• Usage is batch-first and migrates from Azure Table Storage to Cassandra activity storage with TTL.
• Device connection/status history migrates to Cassandra activity storage.
• Mutable current device connectivity is explicitly separated from history and targeted at durable Application Data/Mongo unless focused consistency analysis requires something stronger.
• Observability on the existing API endpoint family is the evidence gate for any later host extraction.

The original RDS-01 through RDS-05 files are retained but rewritten as the new compact server-side sequence rather than leaving stale lease/host cards behind.