Do not require READMEs in generated realism folders

Remove generated README files from docs/screens/realism and update the screens
index to treat realism as a gitignored local QA directory with no README gate.

docs/screens/README.md

@@ -5,7 +5,7 @@ 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)
+- `realism/` — locally generated realism runs (gitignored; no README requirement)
 
 ## Quick preview