R7 custom emoji in decePub: the server's own, administered, picked, suggested and shown

Administration has a Custom emoji section (EmojiPanel, data-admin-section=emoji): the server's emoji by category, added
with a picture streamed from the file, changed (category, picker, disabled, picture; never the shortcode) and deleted,
asked first, with PrivaPub's 409 and 422 in the dialog. EmojiService reads /clientapi/admin/emoji and, for everyone,
/api/v1/custom_emojis, kept a day in localStorage (CustomEmojiCache) and read again after a change here. EmojiPicker
(a DDropdown sheet on a phone, rendered only while open) offers them by category with common unicode emoji, searchable:
the composer writes the choice at the caret, a card and the announcements banner react with it. The composer suggests
custom emoji after `:` and two letters. Custom reactions toggle as :shortcode: and show their picture, notifications of
one too; located posts, announcements and NavMenu's persona names render the server's emoji.

Verified: Release build, 0 errors (the 3 warnings were there before). Not run against PrivaPub or in the pasture.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WpVCoDeM1qUTRp4fXQdfof

Services/AppStatusService.cs

@@ -42,4 +42,11 @@ public class AppStatusService(IJSRuntime jsRuntime)
 
 		// a sideways-scrolling strip of tabs shows its selected tab
 		public void RevealActive(ElementReference strip) => JsSyncRuntime.InvokeVoid("revealActive", strip);
+
+		// where a text field's selection starts and ends (the caret, when nothing is selected), in UTF-16 units as C# counts
+		// them; null when it can't say
+		public int[] CaretOf(ElementReference field) => JsSyncRuntime.Invoke<int[]>("caretOf", field);
+
+		// the field takes the focus with its caret there
+		public void PlaceCaret(ElementReference field, int at) => JsSyncRuntime.InvokeVoid("placeCaret", field, at);
 }