Sway embed plugins

[danieljtrujillo]

Embedded in theDAW, a track's VST3 chain and the LOAD .gan chooser work through theDAW
The browser bridge used to post the desktop sidecar's shapes to theDAW's
routes, which answered 422 or nothing: PARAMS listed no parameters, EDIT
never read the window's state back, RENDER was refused outright, and the
plugin list threw on a .gan without controls.

vst.params posts {plugin_path} to /api/vst/load, turns the descriptors
into the sidecar's rows with the panel's own values laid over them, and
releases the worker with /api/vst/unload. vst.editor posts the plugin
path and its saved state to /api/vst/open-editor and polls
/api/vst/editor-result until the window closes, keeping the captured state
on the track's plugin entry. vst.render posts the clip and the chain to
/api/sway/vst-render and plays the wet file beside the dry one under the
track's wet / dry mix; a clip picked in the browser has no file theDAW can
read and is refused with the fix named. vst.scan answers the array the
panel maps, and vst.status the fields the pill and note read.

.gan plugins take ganfile.js's describe() shape from /api/plugin/list and
/api/plugin/open, so the panel's control rows render. Inside theDAW, LOAD
opens a chooser of theDAW's installed plugins plus "Open a .gan file",
which asks the host with sway/choose-plugin-file and waits for its
sway/plugin-file answer; a host that lists 'plugin-file' in its
sway/host-ready caps gets the dialog's time, any other a short wait and a
notice that it cannot pick files.

renderTrackVst and the PARAMS and EDIT handlers treat an { ok: false }
answer as the failure the desktop rejects with, so no wet media without a
file is ever made.