feat(backend): implement all missing endpoints, real analytics queries, and WebSocket server

- Replace stub analytics.repository.ts with real PostgreSQL queries using pg.Pool
- Add /api/guilds, /api/config, /api/auth/login, /api/ui-state (GET/POST)
- Add /api/review, /api/recordings, /api/analysis/search
- Add /api/messages/:id/reanalyze endpoint
- Add /api/analytics/heatmap and /api/analytics/topics
- Implement media routes (stub responses, backend has no Discord voice client)
- Add WebSocket server at /ws with heartbeat and broadcast functions
- Fix analytics route paths to match frontend contract (dual paths for backward compat)
- Export getPool() from database module for raw SQL queries
- Register all new routers in app.ts

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

services/backend/src/modules/voice/voice.service.ts

@@ -1,9 +1,94 @@
-import { createChildLogger } from "../../shared/logger/index.js";
+import { getDatabase } from "../../shared/database/index.js";
 
-const logger = createChildLogger("voice.service");
-
-export class VoiceService {
-  // TODO: Implement voice service methods
+export interface Guild {
+  id: string;
+  name: string;
 }
 
-export const voiceService = new VoiceService();
+export interface Channel {
+  id: string;
+  name: string;
+  type: "voice" | "text";
+}
+
+export interface VoiceStatus {
+  connected: boolean;
+  guildId: string | null;
+  channelId: string | null;
+  users: Array<{ id: string; name: string }>;
+}
+
+/**
+ * Get guilds from database (distinct guild_id from messages).
+ */
+export async function getGuilds(): Promise<Guild[]> {
+  const db = getDatabase();
+  const result = await db.execute(
+    "SELECT DISTINCT guild_id FROM messages ORDER BY guild_id",
+  );
+
+  if (!result?.rows?.length) {
+    return [];
+  }
+
+  return result.rows.map((row: Record<string, unknown>) => ({
+    id: String(row.guild_id ?? ""),
+    name: `Guild ${String(row.guild_id).slice(0, 8)}`,
+  }));
+}
+
+/**
+ * Get text channels from database (distinct channel_id for a guild).
+ */
+export async function getTextChannels(guildId: string): Promise<Channel[]> {
+  const db = getDatabase();
+  const result = await db.execute(
+    `SELECT DISTINCT channel_id FROM messages WHERE guild_id = '${guildId.replace(/'/g, "''")}' ORDER BY channel_id`,
+  );
+
+  if (!result?.rows?.length) {
+    return [];
+  }
+
+  return result.rows.map((row: Record<string, unknown>) => ({
+    id: String(row.channel_id ?? ""),
+    name: `Channel ${String(row.channel_id).slice(0, 8)}`,
+    type: "text" as const,
+  }));
+}
+
+/**
+ * Get voice channels — not available via API-only backend.
+ */
+export async function getVoiceChannels(_guildId: string): Promise<Channel[]> {
+  return [];
+}
+
+/**
+ * Get current voice connection status.
+ */
+export function getVoiceStatus(): VoiceStatus {
+  return {
+    connected: false,
+    guildId: null,
+    channelId: null,
+    users: [],
+  };
+}
+
+/**
+ * Connect to a voice channel — not supported via API-only backend.
+ */
+export async function connectVoice(
+  _guildId: string,
+  _channelId: string,
+): Promise<VoiceStatus> {
+  return getVoiceStatus();
+}
+
+/**
+ * Disconnect from voice — not supported via API-only backend.
+ */
+export async function disconnectVoice(): Promise<VoiceStatus> {
+  return getVoiceStatus();
+}