docs(marketplace): documentation cleanup, version alignment, architecture doc

- Delete orphan files (.doc-guardian-queue, stale backup, switch-profile.sh)
- Delete stale doc folders (architecture/, designs/, prompts/)
- Create consolidated docs/ARCHITECTURE.md for v9.1.0
- Bump all 12 original plugin versions to 9.0.1
- Fix project-hygiene descriptions (no longer a hook)
- Normalize /rfc, /project, /adr command rows in all docs
- Update CANONICAL-PATHS.md, UPDATING.md, README.md, CLAUDE.md
- COMMANDS-CHEATSHEET.md expanded to one row per sub-command

Version: 9.1.0

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

plugins/doc-guardian/.claude-plugin/plugin.json

@@ -1,7 +1,7 @@
 {
   "name": "doc-guardian",
   "description": "Automatic documentation drift detection and synchronization",
-  "version": "1.1.0",
+  "version": "9.0.1",
   "author": {
     "name": "Leo Miranda",
     "email": "leobmiranda@gmail.com"