Wire ShareButton into list/note/calendar pages; fix nav and calendar select labels

- Add ShareButton to list detail, note editor, and calendar event panel
- Add Settings gear icon to AppNav (core page not in module registry)
- Fix calendar event dialog showing raw UUID: pass explicit children to
  SelectValue so labels display before SelectContent mounts

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/modules/lists/components/list-detail.tsx

@@ -5,6 +5,7 @@ import { Archive, GripVertical, Plus, Trash2 } from "lucide-react";
 import { useEffect, useRef, useState, useTransition } from "react";
 import { Button } from "@/components/ui/button";
 import { Input } from "@/components/ui/input";
+import { ShareButton } from "@/components/share-button";
 import type { ListDetailDto, ListItemDto } from "../server/queries";
 import { getList } from "../server/queries";
 import {
@@ -109,6 +110,7 @@ export function ListDetail({ initialList }: { initialList: ListDetailDto }) {
             {list.type} / {list.openCount} open / {list.doneCount} done
           </div>
         </div>
+        <ShareButton entityType="lists.list" entityId={list.id} canWrite={true} />
         <Button variant="outline" onClick={archiveCurrentList} disabled={isPending}>
           <Archive />
           Archive list