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/multi-session-terminal-ux/.pi-map.index.md

@@ -1,11 +1,11 @@
-# openspec/changes/multi-session-terminal-ux (index)
-dir: openspec/changes/multi-session-terminal-ux
+# multi-session-terminal-ux (index)
+dir: multi-session-terminal-ux
 
 ## role
-Open specification and design documentation for implementing multi-session terminal UX in a web-based tool instance platform
+Design and specification package for implementing multi-session terminal UX support in a web-based tool instance platform.
 ## parent
-index: openspec/changes/.pi-map.index.md
-map: openspec/changes/.pi-map.md
+index: ./.pi-map.index.md
+map: ./.pi-map.md
 ## children
 -
 ## files
@@ -18,8 +18,8 @@ map: openspec/changes/.pi-map.md
 - proposal.md
 - tasks.md
 ## links
-index: openspec/changes/multi-session-terminal-ux/.pi-map.index.md
-map: openspec/changes/multi-session-terminal-ux/.pi-map.md
+index: multi-session-terminal-ux/.pi-map.index.md
+map: multi-session-terminal-ux/.pi-map.md
 ## workflows
 -
 ## dirty

openspec/changes/multi-session-terminal-ux/.pi-map.md

@@ -1,10 +1,10 @@
-# openspec/changes/multi-session-terminal-ux
-dir: openspec/changes/multi-session-terminal-ux
+# multi-session-terminal-ux
+dir: multi-session-terminal-ux
 
-index: openspec/changes/multi-session-terminal-ux/.pi-map.index.md
+index: multi-session-terminal-ux/.pi-map.index.md
 
 ## role
-Open specification and design documentation for implementing multi-session terminal UX in a web-based tool instance platform
+Design and specification package for implementing multi-session terminal UX support in a web-based tool instance platform.
 ## files
 - .openspec.yaml | Defines an open specification for a multi-session terminal user experience project
 - apply-pr1.md | Documents the implementation of database schema, Alembic migration, and TerminalManager multi-session core for a multi-session terminal UX feature. | dep: Alembic, SQLAlchemy, aiosqlite, asyncio, pytest, TerminalSession, TerminalManager, UUIDPrimaryKeyMixin, TimestampMixin, SessionLocal
@@ -15,7 +15,7 @@ Open specification and design documentation for implementing multi-session termi
 - proposal.md | Proposes architectural changes to support multiple concurrent terminal sessions per tool instance with improved UI/UX features | dep: TerminalManager, TerminalSession, api/terminal.py, TerminalComponent, terminal.tsx, WebSocket protocol, database schema
 - tasks.md | A software design document detailing a 12-task implementation plan for adding multi-session terminal UX support to a web application, organized across 3 stacked pull requests with TDD acceptance criteria. | dep: Alembic, SQLAlchemy, FastAPI, WebSocket, React, TypeScript, xterm.js, PTY, UUID, pytest, Jest/RTL
 ## arch
-Specification-driven incremental architecture using stacked PRs (backend→API→frontend), tabbed terminal UI with WebSocket protocol, database-backed session persistence, and TDD acceptance criteria
+Document-driven architecture using stacked PR planning (3 PRs: backend/core, empty/placeholder, frontend/UI), TDD acceptance criteria, and explicit MVP scoping with 5-session concurrency limit.
 ## tags
 terminal, multi, session, apply, alembic, support, design, implementation
 ## symbols