chore(lint): remove all 34 dead-code warnings (verified site by site)

unused-vars (25): leftover imports/types across pages, routes and services;
write-only sickHours accumulator; unused holidayCount pair; test helpers
authPatch/authDelete; TOut dropped from ApiMutationOptions (the hook keeps
its own generic — no call-site changes); requireAuth no longer importable
in customers/warehouse routes (matches the no-bare-auth-reads convention).

useless-assignment (5): initializers proven overwritten on every path
(systemQty x2, hours, writtenSize -> let x: number) and the seed's dead
adminUser reassignment (create kept, assignment dropped).

useless-escape (4): [eE+\-] -> [eE+-] and [\/...] -> [/...] — identical
semantics.

Behavior-neutral; lint 102 -> 68 warnings (0 errors), suite 641 green.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/routes/admin/warehouse.ts

@@ -2,7 +2,7 @@ import { FastifyInstance } from "fastify";
 import multipart from "@fastify/multipart";
 import prisma from "../../config/database";
 import { config } from "../../config/env";
-import { requireAuth, requirePermission } from "../../middleware/auth";
+import { requirePermission } from "../../middleware/auth";
 import { logAudit } from "../../services/audit";
 import { success, error, parseId, paginated } from "../../utils/response";
 import { contentDisposition } from "../../utils/content-disposition";
@@ -2209,7 +2209,7 @@ export default async function warehouseRoutes(
       // Build items with auto-filled system_qty and calculated difference
       const itemsData = await Promise.all(
         body.items.map(async (item) => {
-          let systemQty = 0;
+          let systemQty: number;
 
           if (item.location_id != null) {
             // Get stock at specific location
@@ -2318,7 +2318,7 @@ export default async function warehouseRoutes(
       if (body.items) {
         itemsData = await Promise.all(
           body.items.map(async (item) => {
-            let systemQty = 0;
+            let systemQty: number;
 
             if (item.location_id != null) {
               const loc = await prisma.sklad_item_locations.findUnique({