fix: normalize Turkish search and isolate query item matches

tests/tender-search.test.mjs

@@ -0,0 +1,19 @@
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import {normalizeTenderSearch,matchesTenderSearch,matchingItemResults} from '../src/services/tenderSearch.js';
+test('Turkish search treats case, decomposed characters and spacing consistently across fields',()=>{
+  for(const value of ['IĞDIR','Iğdır','igdir','  IĞDIR  ']) assert.equal(normalizeTenderSearch(value),'igdir');
+  for(const field of ['baslik','kurum']) assert.equal(matchesTenderSearch({[field]:'IĞDIR İL SAĞLIK'},'ığdır'),true);
+  assert.equal(matchesTenderSearch({items:[{ad:'STERİL  TEST KİTİ'}]},'steril test'),true);
+  assert.equal(matchesTenderSearch({kalemler:['İmmünoloji']},'immunoloji'),true);
+  assert.equal(matchesTenderSearch({kalemler:[{ad:'Ölçüm'}]},'olcum'),true);
+  assert.equal(matchesTenderSearch({},'   '),true);
+  assert.equal(matchesTenderSearch({baslik:'Mikroskop'},'hemogram'),false);
+});
+test('old item matches are unavailable immediately when a new query is entered',()=>{
+  const result={query:normalizeTenderSearch('hemogram'),matches:new Map([['2026/1',[{ad:'Hemogram'}]]])};
+  assert.equal(matchingItemResults(result,'HEMOGRAM'),result.matches);
+  assert.equal(matchingItemResults(result,'mikroskop'),null);
+  assert.equal(matchesTenderSearch({ikn:'2026/1',baslik:'Genel sarf'},'mikroskop',matchingItemResults(result,'mikroskop')),false);
+  assert.equal(matchingItemResults(result,''),null);
+});