Add quick commands autocomplete dropdown in chat input

Server-authoritative command list via packet 4050, merged with
client-only commands. Supports keyboard navigation, filtering,
and module-level caching to handle login-time packet timing.

Co-Authored-By: medievalshell <medievalshell@users.noreply.github.com>

src/components/room/widgets/chat-input/ChatInputCommandSelectorView.tsx

@@ -0,0 +1,41 @@
+import { FC, useEffect, useRef } from 'react';
+import { CommandDefinition } from '../../../../api';
+
+interface ChatInputCommandSelectorViewProps
+{
+    commands: CommandDefinition[];
+    selectedIndex: number;
+    onSelect: (command: CommandDefinition) => void;
+    onHover: (index: number) => void;
+}
+
+export const ChatInputCommandSelectorView: FC<ChatInputCommandSelectorViewProps> = props =>
+{
+    const { commands = [], selectedIndex = 0, onSelect = null, onHover = null } = props;
+    const listRef = useRef<HTMLDivElement>(null);
+
+    useEffect(() =>
+    {
+        if(!listRef.current) return;
+
+        const selected = listRef.current.children[selectedIndex] as HTMLElement;
+
+        if(selected) selected.scrollIntoView({ block: 'nearest' });
+    }, [ selectedIndex ]);
+
+    return (
+        <div ref={ listRef } className="absolute bottom-full left-0 w-full bg-[#e8e8e8] border-2 border-black border-b-0 rounded-t-lg max-h-[240px] overflow-y-auto z-[1070]">
+            { commands.map((cmd, index) => (
+                <div
+                    key={ cmd.key }
+                    className={ `px-3 py-1.5 cursor-pointer text-sm flex items-center gap-2 ${ index === selectedIndex ? 'bg-[#283F5D] text-white' : 'hover:bg-gray-300' }` }
+                    onClick={ () => onSelect(cmd) }
+                    onMouseEnter={ () => onHover(index) }
+                >
+                    <span className="font-bold">:{ cmd.key }</span>
+                    <span className={ `text-xs ${ index === selectedIndex ? 'text-gray-300' : 'text-gray-500' }` }>{ cmd.description }</span>
+                </div>
+            )) }
+        </div>
+    );
+};