feat: move sessions to new worktrees

Add a root-session action that creates a generated worktree from the session directory's current branch, transfers uncommitted changes, and moves the parent session plus its descendants through OpenCode's control-plane API.

Reuse existing project/worktree topology and quick-create behavior, keep the UI non-blocking, reconcile live and global session state across directories, and roll back partial moves and failed worktree creation safely.

Split worktree bootstrap readiness into directory-created, git-ready, and setup-ready phases across web and VS Code. Session moves wait for Git readiness while existing setup-aware flows continue waiting for full setup completion, and worktree removal is serialized with active bootstrap tasks.

Expose the move only for idle root sessions, show localized progress and explanatory tooltips in the sidebar, and keep pending/ready worktree metadata synchronized with authoritative session attachments to avoid stale setup indicators.

Add coverage for control-plane payloads, session-state migration, bootstrap phase ordering and compatibility, removal races, progress metadata, and fast-ready attachment races.

packages/ui/src/sync/DOCUMENTATION.md

@@ -100,8 +100,9 @@ VS Code does not run the server permission-auto-accept runtime. The extension ho
    - title update
    - share
    - unshare
-   - archive
-   - delete
+    - archive
+    - delete
+    - move to another worktree directory
    - retention cleanup batch archive/delete
 
 This keeps cold/global lists responsive without requiring a refetch after every change.
@@ -125,6 +126,7 @@ Examples of global-store updates performed in `session-actions.ts`:
 - `shareSession()` / `unshareSession()` -> `upsertSession(result.data)`
 - `archiveSession()` -> `archiveSessions([id], archivedAt)`
 - `deleteSession()` -> `removeSessions([id])`
+- `moveSessionToDirectory()` -> move the session between directory stores and update the global directory index
 
 ## The golden rule