Scene Manager: request publishes missing on this site

- Request (globe) on casting rows and loaded assets whose latest publish
  is not on this site, and Request Missing for all of them, through the
  new wtdcmds command wtd_request_revisions. Requested publishes show
  "requested, waiting for the download".
- The version picker requests a version that is not on this site.
- A 404 explains that the session is gone or wtdcmds is too old.
- Fake server: car (vehicles) with a publish not on this site,
  wtd_request_revisions and /_test/download; 45 checks.
- Tested live: car_paul modeling.blend v001 -> Requested.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

ui/panel.py

@@ -384,6 +384,8 @@ class _SceneCastingPanel:
         row = layout.row(align=True)
         row.scale_y = 1.3
         row.operator(sm.WTD_OT_scene_load.bl_idname, text="Load Missing", icon="IMPORT")
+        if sm.missing_files(context.scene):
+            row.operator(sm.WTD_OT_scene_request.bl_idname, text="Request Missing", icon="URL")
         row.operator(sm.WTD_OT_scene_refresh.bl_idname, text="", icon="FILE_REFRESH")
         casting = sm.STATE.casting.get(oid)
         if casting is None:
@@ -400,16 +402,23 @@ class _SceneCastingPanel:
             have = len(found.get(library.name, [])) if library else 0
             want = asset.get("nb_occurences") or 1
             error = asset.get("error")
-            icon = "ERROR" if error else "CHECKMARK" if have >= want else "IMPORT"
+            file = sm.file_data(asset["file"]["file_oid"], asset["file"]) if asset.get("file") else None
+            latest = (file or {}).get("latest") or {}
+            requested = bool(error) and latest.get("sync_status") == "Requested"
+            if requested:
+                error = f"{latest['name']} requested, waiting for the download"
+            icon = "SORTTIME" if requested else "ERROR" if error else "CHECKMARK" if have >= want else "IMPORT"
             row = col.row(align=True)
-            row.alert = bool(error)
+            row.alert = bool(error) and not requested
             row.label(text=f"{asset['name']}  ({asset.get('asset_type', '')})", icon=icon)
             row.label(text=f"{have}/{want}")
             if not error and have < want:
                 row.operator(sm.WTD_OT_scene_load.bl_idname, text="", icon="IMPORT").asset_oid = asset["oid"]
+            if sm.to_request(file):
+                row.operator(sm.WTD_OT_scene_request.bl_idname, text="", icon="URL").file_oid = file["file_oid"]
             if error:
                 sub = col.row()
-                sub.alert = True
+                sub.alert = not requested
                 _wrapped_label(sub, context, error, icon="BLANK1")
 
         cast = {asset["oid"] for asset in casting["assets"]}
@@ -455,6 +464,8 @@ class _SceneLoadedPanel:
             version.label(text=library.get("wtd_revision", "?"))
             if state == "UPDATE":
                 row.operator(sm.WTD_OT_scene_update.bl_idname, text="", icon="FILE_REFRESH").library = library.name
+            elif state == "PENDING" and sm.to_request(sm.file_data(library["wtd_file_oid"])):
+                row.operator(sm.WTD_OT_scene_request.bl_idname, text="", icon="URL").file_oid = library["wtd_file_oid"]
             row.operator(sm.WTD_OT_scene_pick_revision.bl_idname, text="", icon="COLLAPSEMENU").library = library.name
             row.operator(sm.WTD_OT_scene_remove.bl_idname, text="", icon="X").library = library.name
             if outdated: