Shell: tile settings in a window beside the tile; schemas per tile kind

The gear popover lived inside its tile, so a tile could be too small for its
own settings, and the settings sat on top of the thing they change. It is now
a small window: placed beside the tile (right when there is room, else left,
else over it), clamped to the viewport, moved by a grab bar, closed by
clicking away, Escape, the ✕ or the gear. Settings still apply as they
change — that is the point of putting the window beside the tile.

With it, four pieces of contract the module work needs:

- A picker entry may carry its own `instanceSchema` / `instanceGroups`:
  tiles added from it get settings that fit that tile, nothing else. A tile
  showing one ProPresenter timer has no use for a clock's format switches.
- `instanceGroups[name].toggle` puts a group's on/off switch in its title row
  and dims the body while it is off — the admin page's convention, in the
  popover.
- `select` and `multiselect` in tile settings may take `optionsRoute`;
  `multiselect` also `columns` and `allByDefault` (nothing saved until
  someone flips a switch, so options that turn up later are on too).
- `template`: a text with placeholders built by dragging or clicking the
  variables a module offers into it.

And the ＋ picker's descriptions are tooltips now — the list stays a list.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

server.js

@@ -466,6 +466,11 @@ function sanitizeTileEntry(raw) {
     // at most one tile of this entry per dashboard (the picker greys it out)
     single: raw.single === true,
   };
+  // An entry may offer its own gear settings — a solo timer wants none of a
+  // full tile's switches. Same shape as the manifest's instanceSchema/Groups.
+  for (const key of ['instanceSchema', 'instanceGroups']) {
+    if (raw[key] && typeof raw[key] === 'object') out[key] = raw[key];
+  }
   for (const key of ['minSize', 'defaultSize']) {
     const size = raw[key];
     if (size && Number(size.w) > 0 && Number(size.h) > 0) {