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>

package-lock.json

@@ -1,12 +1,12 @@
 {
   "name": "app-ts",
-  "version": "2.4.33",
+  "version": "2.4.34",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "app-ts",
-      "version": "2.4.33",
+      "version": "2.4.34",
       "license": "ISC",
       "dependencies": {
         "@anthropic-ai/sdk": "^0.102.0",