Document the character development toolchain in the architecture

TODO.md

@@ -181,7 +181,11 @@ verify every distribution path. This is the next minor release after the 0.9.x p
       `check_screenshots.sh` and the pinned vision judge, recording model/spend/verdicts.
 - [ ] Run the manual smoke checklist on every target and attach/link the release-candidate evidence.
 - [ ] Verify the tutorial/campaign/help text at maximum font scale and with the longest strings.
-- [ ] Remove or archive stale plans/notes and confirm no contradictory version/status claims remain.
+- [x] Remove or archive stale plans/notes and confirm no contradictory version/status claims remain.
+- [x] Document the character development toolchain in `docs/architecture.md`: base vs library
+      sources, tool/artifact/gate table, runtime attach/animation contracts and rebuild discipline.
+      (Added §5 "Character development tooling" plus risk and ownership-map updates;
+      documentation check passed.)
 
 ### Release-candidate QA and exit