.NET: Update AIContextProviders to use Microsoft.Extensions.Compliance.Redaction

[westey-m]

Motivation and Context

Addressing SDK review feedback.

#2375

Description

• For places where we redact sensitive data from logs, allow users to provider their own redactor implementations by allowing a Redactor from Microsoft.Extensions.Compliance.Redaction to be supplied.

Contribution Checklist

• The code builds clean without any errors or warnings
• The PR follows the Contribution Guidelines
• All unit tests pass, and I have added new tests where possible
• Is this a breaking change? If yes, add "[BREAKING]" prefix to the title of the PR.

[Copilot]

Pull request overview

Updates .NET AI context providers’ logging redaction to use Microsoft.Extensions.Compliance.Redaction.Redactor, allowing callers to supply a custom redactor while keeping an explicit EnableSensitiveTelemetryData override for unredacted logs.

Changes:

• Add Redactor + EnableSensitiveTelemetryData options to multiple providers and route log payloads through the configured redactor.
• Introduce a shared internal ReplacingRedactor (default placeholder "<redacted>") and MSBuild injection support (InjectSharedRedaction).
• Expand unit tests to validate default vs custom redaction behavior and precedence rules.

Reviewed changes

Copilot reviewed 19 out of 19 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
dotnet/src/Microsoft.Agents.AI/Memory/ChatHistoryMemoryProviderOptions.cs	Adds Redactor option + precedence remarks.
dotnet/src/Microsoft.Agents.AI/Memory/ChatHistoryMemoryProvider.cs	Switches sanitization to a Redactor instance (default placeholder or caller-provided).
dotnet/tests/Microsoft.Agents.AI.UnitTests/Memory/ChatHistoryMemoryProviderTests.cs	Updates tests for default/custom redaction and precedence.
dotnet/src/Microsoft.Agents.AI/TextSearchProviderOptions.cs	Adds EnableSensitiveTelemetryData and Redactor options.
dotnet/src/Microsoft.Agents.AI/TextSearchProvider.cs	Applies redaction to trace log payloads via a Redactor.
dotnet/tests/Microsoft.Agents.AI.UnitTests/Data/TextSearchProviderTests.cs	Adds test coverage for redaction behavior.
dotnet/src/Microsoft.Agents.AI.Mem0/Mem0ProviderOptions.cs	Adds Redactor option + precedence remarks.
dotnet/src/Microsoft.Agents.AI.Mem0/Mem0Provider.cs	Switches sanitization to Redactor instance.
dotnet/tests/Microsoft.Agents.AI.Mem0.UnitTests/Mem0ProviderTests.cs	Updates tests for default/custom redaction and precedence.
dotnet/src/Microsoft.Agents.AI.FoundryMemory/FoundryMemoryProviderOptions.cs	Adds Redactor option + precedence remarks.
dotnet/src/Microsoft.Agents.AI.FoundryMemory/FoundryMemoryProvider.cs	Switches sanitization to Redactor instance.
dotnet/src/Shared/Redaction/ReplacingRedactor.cs	Adds shared internal placeholder redactor implementation.
dotnet/src/Shared/Redaction/README.md	Documents shared redaction injection and package dependency.
dotnet/eng/MSBuild/Shared.props	Adds InjectSharedRedaction injection hook.
dotnet/src/Microsoft.Agents.AI/Microsoft.Agents.AI.csproj	Enables shared redaction injection + adds compliance abstractions package reference.
dotnet/src/Microsoft.Agents.AI.Mem0/Microsoft.Agents.AI.Mem0.csproj	Enables shared redaction injection + adds compliance abstractions package reference.
dotnet/src/Microsoft.Agents.AI.FoundryMemory/Microsoft.Agents.AI.FoundryMemory.csproj	Enables shared redaction injection + adds compliance abstractions package reference.
dotnet/Directory.Packages.props	Pins Microsoft.Extensions.Compliance.Abstractions version.
dotnet/agent-framework-dotnet.slnx	Adds shared redaction files as solution items.