feat: add iOS simulator worktree preview

Adds the worktree service, setup cache seeding, and Metro preview mount for /.sim. Also includes the related startup and mobile sidebar fixes needed by the updated worktree app flow.

docs/development.md

@@ -29,6 +29,7 @@ Root checkout dev is intentionally split across terminals:
 - **Repo dev scripts** default to `$ROOT/.dev/paseo-home`, where `$ROOT` is the current checkout or worktree root. This keeps all dev state scoped to the checkout instead of the packaged desktop app.
 - **`npm run cli -- ...`** runs through the same dev-home wrapper as the dev scripts, so the in-repo CLI automatically targets the current checkout's `.dev/paseo-home` and configured dev daemon endpoint.
 - **Paseo-created worktrees** seed `$PASEO_WORKTREE_PATH/.dev/paseo-home` from `$PASEO_SOURCE_CHECKOUT_PATH/.dev/paseo-home` by copying durable JSON metadata. Runtime files like pid files, sockets, and logs are not copied.
+- **This repo's worktree setup** also best-effort seeds `packages/app/ios` and the newest `.dev/ios-build` entry from the source checkout so iOS simulator services can reuse native project and Xcode cache state when it is safe enough to do so.
 
 Override knobs:
 
@@ -48,6 +49,16 @@ PASEO_DEV_RESET_HOME=1 npm run dev            # clear and reseed the derived wor
 
 In Paseo-managed worktree services, use the injected service environment rather than hardcoded root checkout ports.
 
+### iOS simulator preview service
+
+Paseo worktrees expose the native iOS dev app through the `ios-simulator` service in `paseo.json`. The service URL serves the simulator preview at `/.sim`, so the preview link is `${PASEO_URL}/.sim`.
+
+The service is designed for concurrent worktrees: it derives a deterministic simulator identity from the worktree path, uses the worktree's assigned `PASEO_PORT`, pins `serve-sim` to that simulator UDID, and only tears down that worktree's helper/simulator state. It must not rely on the globally booted simulator or any fixed Metro port.
+
+Worktree setup best-effort seeds the generated iOS project and newest native build cache from the source checkout before the service runs. The service still validates the native project by running Expo prebuild and Xcode; the seed only avoids paying all setup/build cost from a cold worktree every time.
+
+Starting the service must not create, focus, reveal, or leave behind macOS Simulator.app windows. The browser preview is the user-visible simulator surface.
+
 ### Desktop renderer profiling
 
 `npm run dev:desktop` starts Electron with Chromium remote debugging enabled on