[WIP] Implement token caching infrastructure in Node.js SDK

[Copilot]

Thanks for assigning this issue to me. I'm starting to work on it and will keep this PR's description up to date as I form a plan and make progress.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>[AI First Parity] [TASK-002] Implement Token Caching Infrastructure in Node.js SDK</issue_title>
<issue_description>## 📋 Parity Implementation Task: TASK-002

Auto-generated from AiParityTaskList.md by the AI-Parity-Issue-Creation Workflow

🎯 Implementation Goal

This task involves porting existing functionality to achieve parity between language implementations. The functionality described below already exists in the dotnet repo(s) and needs to be implemented in the nodejs language to maintain feature consistency across all SDK implementations.

🔗 Source Repositories

microsoft/Agent365-dotnet

Important: This is not about creating new features, but about bringing the nodejs implementation to parity with existing functionality found in: dotnet

📊 Task Details

• Task ID: `TASK-002`
• Priority: HIGH
• Effort Estimate: LARGE
• Target Language: `nodejs` (where the feature needs to be implemented)
• Exists In: dotnet (repos that already have this functionality)
• Status: Open

📝 Description

✅ Acceptance Criteria

• Token cache interface defined - In-memory token cache implementation - Token expiration handling - Async-safe cache operations - Unit tests for caching logic

🔗 Reference Implementation

Use the following existing implementations as reference for porting to nodejs:
microsoft/Agent365-dotnet/src/Observability/Core/Caching/

🔧 Dependencies

None

📋 Implementation Instructions

1. Study the Reference Implementation: Use the cross-repo-agent to examine the existing code in the dotnet repo(s) to understand the functionality, APIs, and patterns used

• The repos are located at: microsoft/Agent365-dotnet

2. Port to Target Language: Implement equivalent functionality in the nodejs language, following language-specific best practices
3. Maintain Consistency: Ensure the ported functionality provides the same capabilities and, where possible, similar APIs as the reference implementations
4. Include Tests: Port or create equivalent tests to match the coverage and functionality of the reference implementations
5. Update Documentation: Add appropriate documentation and usage examples for the nodejs implementation

💡 Implementation Guidelines for Node.js/TypeScript

When implementing this feature in the TypeScript SDK:

• Review existing code in the TypeScript SDK codebase to understand the structure and patterns
• Follow the coding style, naming conventions, and architectural patterns used in the TypeScript SDK
• Check for configuration files (e.g., .eslintrc.json, tsconfig.json, .prettierrc) that define coding standards
• Ensure your implementation is consistent with existing SDK components
• Include appropriate tests following the testing patterns in the TypeScript SDK
• Follow TypeScript conventions: camelCase naming, proper type definitions, async/await patterns, ES modules

🏷️ Labels

• Priority: HIGH
• Effort: LARGE
• Target: nodejs

🚀 GitHub Copilot Instructions

⚠️ IMPORTANT: Create Only ONE Pull Request

Please complete this entire task in a single pull request. Do not break this work into multiple PRs. All implementation, tests, documentation, and related changes should be included together in one comprehensive PR.

When creating your pull request for this issue, please use the following title format:

Required PR Title Format: `[AI First Parity] [TASK-002] `

Example: `[AI First Parity] [TASK-001] Implement identity/authentication services in Python`

This standardized format helps track all AI First Parity related pull requests and ensures proper categorization in the repository.

⚠️ REQUIRED: Include Reviewer Instructions in PR Description

When creating your pull request, you MUST append the following text exactly as shown below to the end of your PR description. Copy and paste this text verbatim:

---

📝 Instructions for PR Reviewers

🚫 If Parity is Not Needed for This Feature

If you determine during review that this particular feature should NOT be ported to the target implementation (e.g., it's language-specific, deprecated, or not applicable), please follow these steps:

1. Close the PR and delete the branch
2. Close the issue by navigating to the linked issue and closing it
3. Add a comment explaining why parity is not needed (e.g., "Feature is .NET-specific and not applicable to Python implementation" or "Feature deprecated and should not be ported")

Note: Only close if you're certain the feature should not be ported. If the implementation just needs modifications or a different approach, keep the issue open and work with copilot on the PR....

• Fixes [Ignore] Implement Token Caching Infrastructure in Node.js SDK #83

---

💡 You can make Copilot smarter by setting up custom instructions, customizing its development environment and configuring Model Context Protocol (MCP) servers. Learn more Copilot coding agent tips in the docs.

[JonCGit]

🤖 Auto-Assignment

Please review this PR and make any necessary adjustments. You can request that copilot make changes to this PR by tagging them in a comment on this PR with instructions on what to change.

🚫 If Parity is Not Needed for This Feature

If you determine during review that this particular feature should NOT be ported to the target implementation (e.g., it's language-specific, deprecated, or not applicable), please follow these steps:

1. Close the PR and delete the branch
2. Close the issue by navigating to the linked issue and closing it
3. Add a comment on the issue explaining why parity is not needed (e.g., 'Feature is .NET-specific and not applicable to Python implementation' or 'Feature deprecated and should not be ported')

Note: Only close if you're certain the feature should not be ported. If the implementation just needs modifications or a different approach, keep the issue open and work with copilot on the PR.
Note: Do NOT delete the issue. If the issue is deleted, the automated workflow will pick it back up in subsequent runs.

---

Workflow Run: View workflow that created this PR