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/discord-gateway/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/discord-gateway/src/shared/database/migrate.ts

@@ -1,10 +1,10 @@
 import "dotenv/config";
 import { readFile } from "node:fs/promises";
 import { join } from "node:path";
-import { createChildLogger } from "@/shared/logger/index";
 import { drizzle as drizzlePostgres } from "drizzle-orm/node-postgres";
 import { migrate as migratePostgres } from "drizzle-orm/node-postgres/migrator";
 import type { PoolClient } from "pg";
+import { createChildLogger } from "@/shared/logger/index";
 import {
   closeDatabase,
   initializeDatabase,

services/discord-gateway/src/shared/database/schema.ts

@@ -595,8 +595,7 @@ export type DbRetentionPolicyInsert =
 
 // Chatbot Messages
 export type ChatbotMessage = typeof chatbotMessagesTable.$inferSelect;
-export type ChatbotMessageInsert =
-  typeof chatbotMessagesTable.$inferInsert;
+export type ChatbotMessageInsert = typeof chatbotMessagesTable.$inferInsert;
 
 // =============================================================================
 // Moderation Actions (gateway-local)

services/discord-gateway/src/shared/database/schema/messages.ts

@@ -1,8 +1,3 @@
-import {
-  pgAttachmentsTable,
-  pgMessageReviewsTable,
-  pgMessagesTable,
-} from "../../../shared/index.js";
 import {
   bigint as pgBigint,
   boolean as pgBoolean,
@@ -11,6 +6,11 @@ import {
   text as pgText,
   uuid as pgUuid,
 } from "drizzle-orm/pg-core";
+import {
+  pgAttachmentsTable,
+  pgMessageReviewsTable,
+  pgMessagesTable,
+} from "../../../shared/index.js";
 
 // Re-export shared message/attachment/review tables
 export { pgAttachmentsTable, pgMessageReviewsTable, pgMessagesTable };

services/discord-gateway/src/shared/database/schema/meta.ts

@@ -25,5 +25,4 @@ export type UIStateInsert = typeof uiStateTable.$inferInsert;
 export type RetentionPolicy = typeof retentionPoliciesTable.$inferSelect;
 export type RetentionPolicyInsert = typeof retentionPoliciesTable.$inferInsert;
 export type ChatbotMessage = typeof chatbotMessagesTable.$inferSelect;
-export type ChatbotMessageInsert =
-  typeof chatbotMessagesTable.$inferInsert;
+export type ChatbotMessageInsert = typeof chatbotMessagesTable.$inferInsert;

services/discord-gateway/src/shared/database/voiceRecordingRepo.ts

@@ -1,5 +1,5 @@
-import { createChildLogger } from "@/shared/logger/index";
 import { desc, eq } from "drizzle-orm";
+import { createChildLogger } from "@/shared/logger/index";
 import { getDatabase } from "./drizzle.js";
 import {
   type VoiceRecording,