Path B: per-viewport Scrypted devices with UI-driven settings

Convert the Scripts-plugin script from a hardcoded BINDINGS constant
into a DeviceProvider + DeviceCreator + HttpRequestHandler. Each
viewport is now a child Scrypted device under the parent script with
its own Settings page; operators add, edit, and delete viewports
entirely through the Scrypted UI.

Parent (ScryptedViewportProvider):
- DeviceProvider: getDevice(nativeId) instantiates a Viewport, attaches
  its camera event listener, and posts /config. releaseDevice tears
  down stream + listener + child storage entry.
- DeviceCreator: "+ Add Device" on the parent's page shows a small form
  (name / host / camera picker filtered to Camera interfaces /
  orientation choice). createDevice() pre-populates the child's storage
  via deviceManager.getDeviceStorage(nativeId) and registers it under
  the parent.
- Tracks known child nativeIds in its own storage as a JSON array so it
  can eagerly instantiate every child on plugin start (each
  registration + camera subscription happens at load time, not lazily).
- 5-min re-register loop catches devices that rebooted or got new DHCP
  leases.
- HttpRequestHandler routes POST <base>/state on the parent's endpoint;
  body {viewport, state} is matched against child names. Honors the
  spec race rules: every callback cancels any prior stream + safety
  timer for that viewport before applying the new state, and a /frame
  409 stops the stream without echoing sleep back.
- Global tuning (frame_interval_ms) lives on the parent's Settings.

Child (Viewport):
- Settings: host (string), camera (type=device with deviceFilter for
  the Camera interface — the UX win), orientation (choices), idle
  timeout, brightness. All persisted via this.storage.
- putSetting fires onBindingChanged() on the parent so re-register +
  re-subscribe happen immediately when any field changes.

scrypted/README.md rewritten for the UI-driven flow — install + add
device + edit + remove + global tuning + smoke test — no more "edit
BINDINGS and re-save."

scrypted/package.json + tsconfig.json: optional `npm install` so
editors can resolve @scrypted/sdk types. Nothing here ships — install
remains "paste into Scripts plugin." node_modules ignored.

1 files changed, 4 insertions, 0 deletions

diff --git a/.gitignore b/.gitignore
index cb13780..0dcf175 100644
--- a/.gitignore
+++ b/.gitignore
@@ -5,6 +5,10 @@ dependencies.lock
 managed_components/
 /.cache/
 
+# Scrypted-side script: optional local type-checking
+scrypted/node_modules/
+scrypted/package-lock.json
+
 # Emacs lock files
 .#*
 \#*\#