Shell 1.13.0: the Layouts menu lists the tiles a layout holds but the board is not showing, with a ✕ to remove each

A tile whose module stopped offering its picker entry — Slack's Send message
and Quick replies since the Send Message module took them over — kept its
place in the layout and drew nothing, as designed, but still held its grid
cells with no control anywhere to let them go: a dead area the operator
could not place anything in.

The Layouts menu now has a Not shown section, present only while the layout
holds such a tile. One row per tile: its title (or the module's name plus
the variant, or the module id when it is not installed), why in a few words
— "not offered right now", "module disabled", "module needs a newer
ProdDash", "module not installed" — and a drawn ✕ with a tooltip that
removes it, saves the layout and frees the cells, leaving the menu open as
the Grid Size stepper and Alerts do. The section repaints while the menu is
open whenever tiles become offered or stop being, and only when the list
changed. A tile that merely waits for its module keeps its place as before.

GET /api/modules also returns `inactive` — the installed modules that are
not running, id, name and reason only — so a dashboard can tell a disabled
module from one that is not installed. The toast after loading a named
layout now says the Layouts menu can remove the tiles it did not show.
README and the module guide updated.

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

server.js

@@ -2336,8 +2336,17 @@ function handleRequest(req, res) {
 
   /* — shell API — */
   if (urlPath === '/api/modules' && req.method === 'GET') {
+    // Beside what dashboards may load: the installed modules that are not
+    // running, by id and name only, so a tile one of them left in a layout
+    // can say why it is not drawn ("module disabled") instead of guessing at
+    // "not installed". Nothing of their config travels with it.
+    const inactive = [...manifests.keys()].filter((id) => !isActive(id)).map((id) => ({
+      id,
+      name: String(manifests.get(id).name || id),
+      reason: isEnabled(id) ? 'incompatible' : 'disabled',
+    }));
     Promise.all([...manifests.keys()].filter(isActive).map(clientManifest))
-      .then((list) => sendJson(res, 200, { modules: list }))
+      .then((list) => sendJson(res, 200, { modules: list, inactive }))
       .catch((err) => {
         console.error('[proddash] /api/modules failed:', err);
         if (!res.headersSent) sendJson(res, 500, { error: 'Server error.' });