Consolidate architecture docs and add the v1.0.0 roadmap

Make architecture the canonical system/data-flow source, add explicit
documentation ownership and consolidation rules, and mark the old graphics plan
historical. Fix stale README/status/Blender/release claims. Add a full gap
register and milestone roadmap from v0.8 through v1.0.0, including onboarding,
content depth, accessibility/localization, performance, release/legal blockers
and non-blocking future ideas.

docs/asset-tooling.md

@@ -1,6 +1,10 @@
 # Asset Pipeline and Tooling
 
-Everything the game renders is produced or gated by the scripts below. Development-only outputs (AI concept sheets, Blender sources, raw AI fabrics) are gitignored; the audited game assets are committed.
+Everything the game renders is produced or gated by the scripts below. Architecture-level contracts,
+data flow and failure fallbacks are summarized in
+[`architecture.md`](architecture.md#content-and-asset-pipeline-architecture); this page is the
+operational reference. Development-only outputs (AI concept sheets, Blender sources, raw AI fabrics)
+are gitignored; the audited game assets are committed.
 
 ## Image Asset Tools