refactor: comprehensive codebase cleanup and architecture hardening

- Sprint 1 (Quick Wins): Remove dead analytics modules, fix 4 unresolved
  imports, replace 3 console.warn with logger, remove mock-crc import
- Sprint 2 (Architecture): Create MascotChatRepository, AnalysisRepository,
  3 Zod schemas (mascot-chat, analysis, voice), deduplicate error classes,
  move 3 SQL queries from routes to repository
- Sprint 3 (Complexity): Replace 7 any types with proper interfaces,
  extract 6 helpers from prepareMediaMessage (CC 85 -> ~15)
- Sprint 4 (Config): Remove 22 dead env vars from .env, add 30 missing
  vars to .env.example, standardize naming

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

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

@@ -0,0 +1,39 @@
+import { z } from "zod";
+
+export const voiceCommandSchema = z.object({
+  command: z.string().min(1, "command is required"),
+});
+
+export const connectVoiceSchema = z.object({
+  guildId: z.string().min(1, "guildId is required"),
+  channelId: z.string().min(1, "channelId is required"),
+});
+
+export const guildIdParamSchema = z.object({
+  guildId: z.string().min(1),
+});
+
+export const guildSchema = z.object({
+  id: z.string(),
+  name: z.string(),
+  icon: z.string().nullable(),
+});
+
+export const channelSchema = z.object({
+  id: z.string(),
+  name: z.string(),
+  type: z.enum(["voice", "text"]),
+});
+
+export const voiceStatusSchema = z.object({
+  connected: z.boolean(),
+  activeGuildId: z.string().nullable(),
+  activeChannelId: z.string().nullable(),
+  activeChannelName: z.string().nullable(),
+});
+
+export type VoiceCommand = z.infer<typeof voiceCommandSchema>;
+export type ConnectVoice = z.infer<typeof connectVoiceSchema>;
+export type Guild = z.infer<typeof guildSchema>;
+export type Channel = z.infer<typeof channelSchema>;
+export type VoiceStatus = z.infer<typeof voiceStatusSchema>;