rename: opencortex → passepartout across memex

- .gitmodules: update submodule paths (projects/opencortex → projects/passepartout,
  projects/opencortex-contrib → projects/passepartout-contrib)
- gtd.org, README.org: update project references and display names
- check.lisp, gemini-vision.org, agora/TODO.org: update file paths
- dotemacs: update agenda paths and template config
- system/plans/: update all flight plan references
- system/backups/: update monolithic backup references

check.lisp

@@ -1,5 +1,5 @@
 (handler-case
-    (with-open-file (s "/home/user/memex/projects/opencortex/skills/org-skill-config-manager.org")
+    (with-open-file (s "/home/user/memex/projects/passepartout/skills/org-skill-config-manager.org")
       (loop for line = (read-line s nil)
             while line
             do (when (search "#+begin_src lisp" line)