chore: archive 15 completed OpenSpec changes

Move the following audited-and-implemented changes into
openspec/changes/archive/2026-06-12-completed-changes-archive/:

- backend-frontend-refactoring
- config-profile-git-mounts
- config-profile-includes-ui
- config-profile-multi-repo-mounts
- container-monitoring-notifications
- git-mount-url-validation
- home-path-expansion
- mobile-terminal-ux
- mount-specificity-ordering
- notification-center
- persistent-terminal-sessions
- session-list-overhaul
- ssh-key-mounting
- terminal-fullscreen-unified-header
- tool-session-progress-and-updates

Also regenerated .pi-map*.md files for openspec/changes so the
remaining active changes (multi-session-terminal-ux, reorganize-long-files,
working-copies, workspace-first-ui) reflect the new layout.

openspec/changes/archive/2026-05-25-mobile-app-usability/specs/.pi-map.index.md

@@ -1,34 +1,34 @@
-# openspec/changes/archive/2026-05-25-mobile-app-usability/specs (index)
-dir: openspec/changes/archive/2026-05-25-mobile-app-usability/specs
+# archive/2026-05-25-mobile-app-usability/specs (index)
+dir: archive/2026-05-25-mobile-app-usability/specs
 
 ## role
-Contains archived specification documents from a mobile app usability improvement initiative dated May 25, 2026.
+Contains archived mobile app usability specifications from May 2026, preserving historical design requirements for reference or compliance purposes.
 ## parent
-index: openspec/changes/archive/2026-05-25-mobile-app-usability/.pi-map.index.md
-map: openspec/changes/archive/2026-05-25-mobile-app-usability/.pi-map.md
+index: archive/2026-05-25-mobile-app-usability/.pi-map.index.md
+map: archive/2026-05-25-mobile-app-usability/.pi-map.md
 ## children
-- openspec/changes/archive/2026-05-25-mobile-app-usability/specs/frontend-foundation
-  index: openspec/changes/archive/2026-05-25-mobile-app-usability/specs/frontend-foundation/.pi-map.index.md
-  map: openspec/changes/archive/2026-05-25-mobile-app-usability/specs/frontend-foundation/.pi-map.md
-- openspec/changes/archive/2026-05-25-mobile-app-usability/specs/mobile-navigation
-  index: openspec/changes/archive/2026-05-25-mobile-app-usability/specs/mobile-navigation/.pi-map.index.md
-  map: openspec/changes/archive/2026-05-25-mobile-app-usability/specs/mobile-navigation/.pi-map.md
-- openspec/changes/archive/2026-05-25-mobile-app-usability/specs/mobile-responsive-layouts
-  index: openspec/changes/archive/2026-05-25-mobile-app-usability/specs/mobile-responsive-layouts/.pi-map.index.md
-  map: openspec/changes/archive/2026-05-25-mobile-app-usability/specs/mobile-responsive-layouts/.pi-map.md
-- openspec/changes/archive/2026-05-25-mobile-app-usability/specs/mobile-session-management
-  index: openspec/changes/archive/2026-05-25-mobile-app-usability/specs/mobile-session-management/.pi-map.index.md
-  map: openspec/changes/archive/2026-05-25-mobile-app-usability/specs/mobile-session-management/.pi-map.md
-- openspec/changes/archive/2026-05-25-mobile-app-usability/specs/session-lifecycle-ux
-  index: openspec/changes/archive/2026-05-25-mobile-app-usability/specs/session-lifecycle-ux/.pi-map.index.md
-  map: openspec/changes/archive/2026-05-25-mobile-app-usability/specs/session-lifecycle-ux/.pi-map.md
-- openspec/changes/archive/2026-05-25-mobile-app-usability/specs/tool-instances
-  index: openspec/changes/archive/2026-05-25-mobile-app-usability/specs/tool-instances/.pi-map.index.md
-  map: openspec/changes/archive/2026-05-25-mobile-app-usability/specs/tool-instances/.pi-map.md
+- archive/2026-05-25-mobile-app-usability/specs/frontend-foundation
+  index: archive/2026-05-25-mobile-app-usability/specs/frontend-foundation/.pi-map.index.md
+  map: archive/2026-05-25-mobile-app-usability/specs/frontend-foundation/.pi-map.md
+- archive/2026-05-25-mobile-app-usability/specs/mobile-navigation
+  index: archive/2026-05-25-mobile-app-usability/specs/mobile-navigation/.pi-map.index.md
+  map: archive/2026-05-25-mobile-app-usability/specs/mobile-navigation/.pi-map.md
+- archive/2026-05-25-mobile-app-usability/specs/mobile-responsive-layouts
+  index: archive/2026-05-25-mobile-app-usability/specs/mobile-responsive-layouts/.pi-map.index.md
+  map: archive/2026-05-25-mobile-app-usability/specs/mobile-responsive-layouts/.pi-map.md
+- archive/2026-05-25-mobile-app-usability/specs/mobile-session-management
+  index: archive/2026-05-25-mobile-app-usability/specs/mobile-session-management/.pi-map.index.md
+  map: archive/2026-05-25-mobile-app-usability/specs/mobile-session-management/.pi-map.md
+- archive/2026-05-25-mobile-app-usability/specs/session-lifecycle-ux
+  index: archive/2026-05-25-mobile-app-usability/specs/session-lifecycle-ux/.pi-map.index.md
+  map: archive/2026-05-25-mobile-app-usability/specs/session-lifecycle-ux/.pi-map.md
+- archive/2026-05-25-mobile-app-usability/specs/tool-instances
+  index: archive/2026-05-25-mobile-app-usability/specs/tool-instances/.pi-map.index.md
+  map: archive/2026-05-25-mobile-app-usability/specs/tool-instances/.pi-map.md
 ## files
 ## links
-index: openspec/changes/archive/2026-05-25-mobile-app-usability/specs/.pi-map.index.md
-map: openspec/changes/archive/2026-05-25-mobile-app-usability/specs/.pi-map.md
+index: archive/2026-05-25-mobile-app-usability/specs/.pi-map.index.md
+map: archive/2026-05-25-mobile-app-usability/specs/.pi-map.md
 ## workflows
 -
 ## dirty