Add documentation folder READMEs and visual previews

Create an index README in docs/ and every tracked docs subfolder, with relative
image galleries for Blender previews, screen designs, screenshots and concepts.
Generated realism-run READMEs were also created on disk but remain gitignored.
Validate all Markdown/image links.

docs/screens/README.md

@@ -0,0 +1,16 @@
+# Screens and Visual Evidence
+
+Visual references and generated QA evidence for Gig Line.
+
+- [`concepts/README.md`](concepts/README.md) — AI-assisted realism concept frames
+- [`designs/README.md`](designs/README.md) — screen-design mockups
+- [`../screenshots/README.md`](../screenshots/README.md) — committed game gallery
+- [`realism/README.md`](realism/README.md) — locally generated realism runs (gitignored)
+
+## Quick preview
+
+| Screen | Reference | Current capture |
+| --- | --- | --- |
+| Venue | <img src="designs/venue_overview.png" width="320" alt="Venue design"> | <img src="../screenshots/01-venue-overview.png" width="320" alt="Venue capture"> |
+| Joke Shop | <img src="designs/joke_shop_queue.png" width="320" alt="Joke Shop design"> | <img src="../screenshots/12-joke-shop.png" width="320" alt="Joke Shop capture"> |
+| TV Studio | <img src="designs/studio_arrival.png" width="320" alt="Studio design"> | <img src="../screenshots/13-studio-arrival.png" width="320" alt="Studio capture"> |