Merge main's public workflow assets into the config fix

what changed: Carry the merged workflow PNG and asset guide into PR415 before its final current-base CI check.

why: PR414 landed while the already accepted config-fix commit was being published; GitHub's strict checks require the current base.

what it touched: Only docs/assets/README.md and docs/assets/research-kit-workflow.png are added to the locally accepted a6d6328 tree. The issue #364 implementation remains in its original task commit.

what you verified: verified - #364's normal full commit gate accepted a6d6328; all seven PR414 CI jobs passed in run38562865947 before its expected-head merge to main3d34bfbd. The staged delta is guarded to exactly the two documentation assets, and all other tracked file blobs are compared before commit. The normal documentation commit gate and final PR415 CI follow.

what you got wrong and fixed: nothing to report.

Author: StepenkoAnatoli

docs/assets/README.md

@@ -0,0 +1,18 @@
+# Project workflow preview
+
+[`research-overview.svg`](research-overview.svg) is the editable source used at
+the top of the project README. [`research-kit-workflow.png`](research-kit-workflow.png)
+is the same illustration exported at 1440 × 820 for community posts and services
+that require a raster image. It illustrates the workflow; it is not a screenshot
+of a product interface.
+
+The preview follows the project from framing questions through collection,
+source review, and the configured checks, then to an authored brief for the
+builder. Its footer keeps source review distinct from a passing check.
+
+Suggested alt text: “Research-Kit workflow: frame questions, collect primary
+sources, review evidence, run checks, and hand an authored brief to the builder.”
+
+When sharing the image, link to the [repository](https://github.com/StepenkoAnatoli/Research-Kit)
+so readers can find the setup guide, source, contribution instructions, and
+[license](../../LICENSE).