Make Lite FinOps AG-aware (#980)

[erikdarlingdata]

Problem

Split out from #976. Lite's FinOps determined the SQL Server edition with SERVERPROPERTY('Edition') and nothing else. On an Availability Group readable secondary that returns "Enterprise Edition" just like the primary, so FinOps:

• recommended "Enterprise → Standard would save ~$X/mo" on a replica whose edition can't be changed independently — every replica in an AG must run the same edition; and
• gave no indication in the inventory that the instance was a secondary at all.

Change

• GetAgReplicaRoleAsync — detects Primary / Secondary / Standalone from sys.dm_hadr_availability_replica_states. The DMV is referenced only inside OBJECT_ID-guarded dynamic SQL, so the batch stays valid on Azure SQL Database and non-AG instances (both return Standalone).
• GetRecommendationsAsync — on an Enterprise instance that is an AG secondary, it now emits a single informational Licensing note ("edition/licensing decisions apply to the whole AG, evaluate on the primary; a passive secondary may be SA-covered") instead of the downgrade recommendations and savings estimates.
• GetServerPropertiesLiveAsync — also returns the replica role, surfaced as a new AG Role column in the FinOps server inventory grid (ServerPropertyRow.AgReplicaRole / AgReplicaRoleDisplay).

Test plan

• dotnet build Lite/PerformanceMonitorLite.csproj -c Debug — full rebuild, 0 warnings, 0 errors.
• The AG-role T-SQL and the full modified GetServerPropertiesLiveAsync batch were run against SQL Server 2016, 2019, and 2022 — all return Standalone on these non-AG instances with no errors, confirming the OBJECT_ID guard and the combined batch are valid across versions.
• The Secondary path could not be exercised (no AG in the test environment); the role logic (MAX(CASE role = 1/2 …) over is_local = 1) is standard.

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