[CK DSL] Link provider README to design plan

Add a "Design plan" section to the ck-dsl-provider README pointing at
the CK DSL hipDNN Provider plan as the source of truth for milestone
scope, the runtime embedded-Python architecture, and resolved design
questions.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: DarylHawkinsAMD

dnn-providers/ck-dsl-provider/README.md

@@ -185,3 +185,15 @@ this plugin is the first embedder).
 
 GPU-gated tests skip cleanly on hosts without a HIP-visible device;
 the integration test additionally skips on non-gfx950 hardware.
+
+## Design plan
+
+The provider's architecture, milestone scope, and resolved design
+questions are recorded in the implementation plan:
+
+- [CK DSL hipDNN Provider — Plan](../../projects/composablekernel/python/ck_dsl/dsl_docs/hipdnn_provider/plan.md)
+
+This document is the source of truth for the Milestone 1 goal and
+non-goals, the runtime embedded-Python architecture, and the rationale
+behind decisions such as the embedded interpreter, pybind11 binding,
+and provider-local compile service that are summarised above.