docs: explain how to actually run the VirtualHere passthrough example

The VirtualHere DualSense recipe linked the `virtualhere-dualsense.ts` SDK
example as a deployable recipe but skipped everything needed to run it: that
VirtualHere is a server (couch) + client (host) pair, and that the example —
like every example — imports `../src/index.js`, which only resolves inside the
SDK repo. A user copying it out had no way to know they must
`bun add @punktfunk/host` and swap that import.

- automation.md: rewrite the recipe into a full walkthrough — the two-sided
  VirtualHere setup, the `-t` verbs, the zero-code hooks version, and a new
  scripted section with exact deploy steps, env vars, and running it as a
  service (its own SIGTERM handler makes `systemctl stop` release the pad).
- sdk/README.md: say how to run an example in-repo vs deployed on a host.
- virtualhere-dualsense.ts: header note on the import swap + service setup,
  since that file is where the doc link lands.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

sdk/examples/virtualhere-dualsense.ts

@@ -15,6 +15,11 @@
 //   VH_DEVICE=couch-deck.11 bun examples/virtualhere-dualsense.ts   # address from `-t LIST`
 //   VH_DEVICE=DualSense     bun examples/virtualhere-dualsense.ts   # …or match by name substring
 //
+// To run this *outside* the repo (the normal case), drop it in its own dir, `bun add
+// @punktfunk/host`, and change the import below from `../src/index.js` to `@punktfunk/host`; then
+// keep it alive as a systemd user unit (its SIGTERM release hands the pad back on `systemctl
+// stop`). Full walkthrough: docs → Events & hooks → "full controller passthrough (VirtualHere)".
+//
 // Env: VH_DEVICE      required — a VirtualHere address (`server.port`) or a device-name substring.
 //      VH_CLIENT      client binary. Default `vhclientx86_64` (Linux); Windows `vhui64.exe`,
 //                     macOS `vhclientosx`, ARM Linux `vhclientarm64`.