chore(lint): biome cleanup across services — format, sort imports, drop unused

- discord-gateway: 74 lint errors -> 0 (format, import sorting, unused
  imports/vars, dead breath var)
- backend: format + sort imports (11 warnings left: noExplicitAny)
- frontend: remove unused imports, drop dead breathing var, fix
  useExhaustiveDependencies (scroll keyed on messages), a11y biome-ignore
  for drag surface + stopPropagation container (mouse-only gestures)
- remaining warnings are false positives: index keys on static lists,
  <img> in static export (next/image unsupported), noExplicitAny

tsc --noEmit clean on all 3 services; vitest green (60+36).

services/backend/src/shared/config/index.ts

@@ -160,8 +160,6 @@ export const configSchema = z
       .default(30000)
       .describe("Timeout for individual LLM moderation calls"),
 
-
-
     // ── AI Analysis Timing ──────────────────────────────────────────────
     AI_ANALYSIS_DEBOUNCE_MS: z.coerce.number().positive().default(500),
     AI_ANALYSIS_RECOVERY_INTERVAL_MS: z.coerce

services/backend/src/shared/database/init.ts

@@ -1,6 +1,6 @@
-import { createChildLogger } from "../logger/index.js";
 import { drizzle } from "drizzle-orm/node-postgres";
 import type { Pool, PoolClient } from "pg";
+import { createChildLogger } from "../logger/index.js";
 import { closePool, createPoolFromConfig } from "./pool.js";
 
 const logger = createChildLogger("database.init");

services/backend/src/shared/database/schema.ts

@@ -592,5 +592,4 @@ export type DbRetentionPolicyInsert =
 
 // Chatbot Messages
 export type ChatbotMessage = typeof chatbotMessagesTable.$inferSelect;
-export type ChatbotMessageInsert =
-  typeof chatbotMessagesTable.$inferInsert;
+export type ChatbotMessageInsert = typeof chatbotMessagesTable.$inferInsert;

services/backend/src/shared/middlewares/index.ts

@@ -1,7 +1,7 @@
-import { AppError, ValidationError } from "@/shared/errors/index";
-import { createChildLogger } from "@/shared/logger/index";
 import type { NextFunction, Request, Response } from "express";
 import type { ZodSchema } from "zod";
+import { AppError, ValidationError } from "@/shared/errors/index";
+import { createChildLogger } from "@/shared/logger/index";
 
 const logger = createChildLogger("middleware");
 

services/backend/src/shared/redis/index.ts

@@ -1,4 +1,6 @@
 import { randomUUID } from "node:crypto";
+import Redis from "ioredis";
+import { config } from "../config/index.js";
 import {
   BACKEND_COMMAND,
   BACKEND_COMMAND_REPLY_PREFIX,
@@ -6,8 +8,6 @@ import {
   type CommandReply,
 } from "../index.js";
 import { createChildLogger } from "../logger/index.js";
-import Redis from "ioredis";
-import { config } from "../config/index.js";
 
 const logger = createChildLogger("redis.command-channel");