Let plugins add contextual workspace tools (#3465)

* feat(plugins): add workspace panels and command center contributions

Give local plugins contextual UI entry points without making the daemon interpret client placement or callbacks. Panels receive stable IDs and read cached client state through required selectors with shallow equality, avoiding unrelated guest rerenders and context-discovery RPCs.

* fix(plugins): align shared client state ownership

Workspace panels and Command Center callbacks consume the same frozen client snapshots, so their adapter belongs to the plugin boundary rather than either contribution surface. Refresh the Nix dependency hash for the selector-store dependency added by this feature.

public-docs/sdk/reference.md

@@ -106,7 +106,7 @@ Creation options include `config`, `cwd`, `parent`, `title`, `prompt`, `env`, `o
 | `archive(workspaceOrId)` | `PaseoWorkspaceArchiveResult` | Archives without first creating a handle.                                         |
 | `subscribe(handler)`     | Unsubscribe function          | Listens for connection-local workspace updates. Call `list({ subscribe })` first. |
 
-A workspace handle exposes `id`, `projectId`, `directory`, `name`, `status`, `current()`, `refresh()`, `archive()`, and `subscribe()`. Use `workspace.agents.create(options)` to create an agent without repeating the workspace ID or directory.
+A workspace handle exposes `id`, `projectId`, `directory`, `name`, `status`, `current()`, `refresh()`, `setTitle(title)`, `archive()`, and `subscribe()`. Pass `null` to `setTitle` to restore the derived workspace name. Use `workspace.agents.create(options)` to create an agent without repeating the workspace ID or directory.
 
 ## `client.providers`