docs: update API reference for management classes and methods

Add documentation for new management API classes and methods:
- Add manage_storage_dr and manage_metrics functions
- Add StorageDRManager with all methods
- Add MetricsManager with get_workspace_group_metrics
- Add UserInvitation class for user invitation management
- Add new UsersManager invitation methods
- Add StorageDRCompute, UsageItem, and BillingUsageItem classes
- Correct WorkspaceGroupMetric to WorkspaceGroupMetrics

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: kesmit13

docs/src/api.rst

@@ -243,6 +243,8 @@ object that can be used to interact with the Management API.
    manage_users
    manage_audit_logs
    manage_private_connections
+   manage_storage_dr
+   manage_metrics
 
 
 WorkspaceManager
@@ -485,6 +487,11 @@ They allow you to retrieve and manage users in your organization.
    UsersManager
    UsersManager.get_user
    UsersManager.get_user_identity_roles
+   UsersManager.create_user_invitation
+   UsersManager.get_user_invitation
+   UsersManager.list_user_invitations
+   UsersManager.delete_user_invitation
+   UsersManager.user_invitations
 
 
 User
@@ -499,6 +506,17 @@ User objects are retrieved from :meth:`UsersManager.get_user`.
    User.identity_roles
 
 
+UserInvitation
+..............
+
+UserInvitation objects are returned by the various UsersManager invitation methods.
+
+.. autosummary::
+   :toctree: generated/
+
+   UserInvitation
+
+
 AuditLogsManager
 ................
 
@@ -596,36 +614,83 @@ IdentityRole objects are used by both teams and users management for role inform
    IdentityRole
 
 
+StorageDRManager
+................
+
+StorageDRManager objects are returned by the :func:`manage_storage_dr` function.
+They allow you to manage storage disaster recovery for your organization.
+
+.. currentmodule:: singlestoredb.management.storage_dr
+
+.. autosummary::
+   :toctree: generated/
+
+   StorageDRManager
+   StorageDRManager.get_status
+   StorageDRManager.get_available_regions
+   StorageDRManager.setup_storage_dr
+   StorageDRManager.start_failover
+   StorageDRManager.start_failback
+   StorageDRManager.start_pre_provision
+   StorageDRManager.stop_pre_provision
+
+
 Storage DR
 ----------
 
 Storage Disaster Recovery objects provide information about replicated databases
 and disaster recovery regions.
 
-.. currentmodule:: singlestoredb.management.storage_dr
-
 .. autosummary::
    :toctree: generated/
 
    ReplicatedDatabase
    StorageDRStatus
    StorageDRRegion
+   StorageDRCompute
+
+
+MetricsManager
+..............
+
+MetricsManager objects are returned by the :func:`manage_metrics` function.
+They allow you to retrieve metrics for your organization.
+
+.. currentmodule:: singlestoredb.management.metrics
+
+.. autosummary::
+   :toctree: generated/
+
+   MetricsManager
+   MetricsManager.get_workspace_group_metrics
 
 
 Metrics
 -------
 
 Metrics objects provide workspace group metrics and data points.
 
-.. currentmodule:: singlestoredb.management.metrics
-
 .. autosummary::
    :toctree: generated/
 
-   WorkspaceGroupMetric
+   WorkspaceGroupMetrics
    MetricDataPoint
 
 
+Billing Usage
+-------------
+
+Billing Usage objects provide usage and billing information for workspaces.
+
+.. currentmodule:: singlestoredb.management.billing_usage
+
+.. autosummary::
+   :toctree: generated/
+
+   UsageItem
+   BillingUsageItem
+
+
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