[liftrmongodb] Add C# clientName renames for tier/region models (#44201)

* [liftrmongodb] Add C# clientName renames for tier/region models

Rename RegionsByTierResponse, TierLimitReachedResponse, TierRegions, and ProjectLimitStatus to MongoDBAtlas*-prefixed C# names. The two Response models also adopt the 'Result' suffix to satisfy the AZC0030 analyzer. Client-only (csharp) renames; the wire contract is unchanged.

* [liftrmongodb] Use PascalCase ClusterTier member names (Free/Flex) for csharp

* [liftrmongodb] Rename backups property to IsBackupsEnabled for csharp

Add @@clientName rename for ClusterProperties.backups -> IsBackupsEnabled
to satisfy BOOL001 (.NET bool properties need Is/Has/Can prefix).
Wire name and nullability unchanged.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

---------

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: sharmaanuj334

specification/liftrmongodb/MongoDB.Atlas.Management/client.tsp

@@ -55,3 +55,40 @@ using MongoDB.Atlas;
   "csharp"
 );
 @@clientName(MongoDB.Atlas.ClusterTier, "MongoDBAtlasClusterTier", "csharp");
+
+// Emit PascalCase member names for the ClusterTier extensible enum to match the
+// JavaScript SDK convention (Free/Flex). The wire values ("FREE"/"FLEX") are
+// unchanged; this only affects the C# member identifiers. M10/M30 are already
+// PascalCase, so they need no rename.
+@@clientName(MongoDB.Atlas.ClusterTier.FREE, "Free", "csharp");
+@@clientName(MongoDB.Atlas.ClusterTier.FLEX, "Flex", "csharp");
+
+// Boolean property: use the .NET "Is*" assertion-style name. The wire name
+// ("backups") and nullability (bool?) are unchanged; this only renames the
+// public C# property identifier.
+@@clientName(
+  MongoDB.Atlas.ClusterProperties.backups,
+  "IsBackupsEnabled",
+  "csharp"
+);
+
+// Tier and region preview models. Apply the MongoDBAtlas* prefix for naming
+// consistency, and rename the "Response" suffix to "Result" so the public model
+// names satisfy the AZC0030 analyzer. Client-only (csharp) renames; the wire
+// contract is unchanged.
+@@clientName(
+  MongoDB.Atlas.RegionsByTierResponse,
+  "MongoDBAtlasRegionsByTierResult",
+  "csharp"
+);
+@@clientName(
+  MongoDB.Atlas.TierLimitReachedResponse,
+  "MongoDBAtlasTierLimitReachedResult",
+  "csharp"
+);
+@@clientName(MongoDB.Atlas.TierRegions, "MongoDBAtlasTierRegions", "csharp");
+@@clientName(
+  MongoDB.Atlas.ProjectLimitStatus,
+  "MongoDBAtlasProjectLimitStatus",
+  "csharp"
+);