Add Roadmap document and navigation link

Create docs/roadmap.md with spec implementation tracking, current focus
areas, milestones, and versioning references. Add top-level Roadmap link
in docs/toc.yml before the Versioning entry.

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

Author: jeffhandley

docs/roadmap.md

@@ -0,0 +1,27 @@
+---
+title: C# SDK Roadmap
+author: jeffhandley
+description: ModelContextProtocol C# SDK roadmap and spec implementation tracking
+uid: roadmap
+---
+## Spec Implementation Tracking
+
+The C# SDK tracks implementation of MCP spec components using the [modelcontextprotocol project boards](https://github.com/orgs/modelcontextprotocol/projects), with a dedicated project board for each spec revision. For example, see the [2025-11-25 spec revision board](https://github.com/orgs/modelcontextprotocol/projects/26).
+
+## Current Focus Areas
+
+### Next Spec Revision
+
+The next MCP specification revision is being developed in the [protocol repository](https://github.com/modelcontextprotocol/modelcontextprotocol). The C# SDK already has experimental support for [Tasks](concepts/tasks/tasks.md), which will be updated as the specification is revised.
+
+### Feedback and End-to-End Scenarios
+
+The C# SDK team is actively responding to feedback and continuing to explore end-to-end scenarios for opportunities to add more APIs that implement common patterns.
+
+## Milestones
+
+See the [milestones page](https://github.com/modelcontextprotocol/csharp-sdk/milestones) to see which issues and features are being planned for future versions.
+
+## Versioning
+
+For more information about the C# SDK's approach to versioning, breaking changes, and support, see the [Versioning](versioning.md) documentation.

docs/toc.yml

@@ -3,6 +3,8 @@ items:
   href: concepts/index.md
 - name: API Reference
   href: api/ModelContextProtocol.yml
+- name: Roadmap
+  href: roadmap.md
 - name: Versioning
   href: versioning.md
 - name: Experimental APIs