* 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.
* feat(client): publish the TypeScript SDK surface
Make the high-level client API usable for external integrations and document complete agent, workspace, provider, event, and recipe flows.
* fix(client): correlate provider snapshots by daemon cwd
Return the daemon's canonical snapshot identity so waitForReady can match updates for relative, tilde, and otherwise non-canonical paths without duplicating filesystem rules in the SDK.
* test(server): make snapshot cwd assertion portable
* fix(client): gate canonical provider snapshot waits
Older daemons do not expose the canonical snapshot identity needed to correlate workspace updates safely. Require the advertised capability and fail with an update-host message instead of guessing across workspaces.
