[SkyDevLab]

Fixes #18895

Description

Following the accepted API proposal, this PR introduces UseCommandTimeout overloads on DatabaseFacade (RelationalDatabaseFacadeExtensions):

public static IDisposable UseCommandTimeout(this DatabaseFacade databaseFacade, int? timeout)
public static IDisposable UseCommandTimeout(this DatabaseFacade databaseFacade, TimeSpan timeout)

Key Behaviors

• Temporarily sets the command timeout for the lifetime of the returned IDisposable scope.
• Restores the previous command timeout on scope disposal (including when exceptions occur).
• Supports nested scopes.
• Handles Timeout.InfiniteTimeSpan (mapped to 0) and validates negative timeouts consistently with SetCommandTimeout.
• Updated public API baseline in \EFCore.Relational.baseline.json.
• Added tests covering scoped execution, nested scopes, exception safety, and argument validation.

[Copilot]

🟡 Changes recommended

Public API documentation should clarify the supported null and infinite-timeout behaviors before approval.

1 open issue

• Document null timeout reset semantics · New

What changed in this PR

This pull request introduces scoped command-timeout configuration for relational DatabaseFacade instances, with nested scopes and exception-safe restoration.

Changes:

• Adds UseCommandTimeout overloads for nullable seconds and TimeSpan values.
• Supports nested scopes, restoration, validation, and infinite-timeout handling.
• Adds relational and SQL Server tests.
• Updates the relational public API baseline.

File	Summary
test/​EFCore.SqlServer.Tests/​Extensions/​SqlServerDatabaseFacadeExtensionsTest.cs	Covers scoping, nesting, restoration, exception safety, infinite timeouts, and validation.
test/​EFCore.Relational.Tests/​Extensions/​RelationalDatabaseFacadeExtensionsTest.cs	Verifies behavior for non-relational providers.
src/​EFCore.Relational/​Extensions/​RelationalDatabaseFacadeExtensions.cs	Implements the scoped timeout APIs and restoration logic. Minor documentation updates should clarify null reset behavior and Timeout.InfiniteTimeSpan mapping.
src/​EFCore.Relational/​EFCore.Relational.baseline.json	Records the two new public overloads.

_{Review effort: Lite}