fix(voice): proper shadcn select dropdowns + top reactors leaderboard

- ui/select: trigger default w-full h-9 (was w-fit h-8 — selects rendered
  tiny/misaligned); callers keep size override via className
- VoiceConnectionCard: labeled full-width h-10 selects (Server/Guild +
  Voice Channel), guild icon + name in options, channel type icon +
  'no akses' tag, empty states, htmlFor/id a11y wiring
- GuildSelector sidebar + messages channel filter bumped to match
- Backend GET /api/dashboard/reactors: top users by net reactions given
  (adds-removes) + messages_reacted + emojis_used
- Reactions tab: second 'Top reaktor' leaderboard panel

services/frontend/src/lib/api/dashboard.ts

@@ -6,6 +6,7 @@ import type {
   PaginatedChannels,
   PaginatedUsers,
   TopReactedMessage,
+  TopReactor,
 } from "@/lib/types";
 import { api } from "./client";
 
@@ -44,4 +45,7 @@ export const dashboardApi = {
 
   getTopReactions: (limit = 20) =>
     api.get<TopReactedMessage[]>(`/api/dashboard/reactions?limit=${limit}`),
+
+  getTopReactors: (limit = 20) =>
+    api.get<TopReactor[]>(`/api/dashboard/reactors?limit=${limit}`),
 };

services/frontend/src/lib/types/dashboard.ts

@@ -116,3 +116,12 @@ export interface TopReactedMessage {
   reaction_count: number;
   top_emojis: TopReactedEmoji[];
 }
+
+export interface TopReactor {
+  user_id: string;
+  username: string;
+  net_count: number;
+  adds_count: number;
+  messages_reacted: number;
+  emojis_used: number;
+}