fix: harden import preflight admission

Keep configured size-limit counts identical to real queue admission, invalidate cancelled import generations, preserve explicit empty destination choices, normalize Windows namespace aliases, inspect files through one read handle, and retain exact rejection balances.

renderer/app.js

@@ -1285,14 +1285,17 @@ function closeHosterModal() {
 }
 
 async function applyHosterSelection() {
+  if (_pendingImportInspections > 0) return false;
   selectedUploadHosters = Array.from(document.querySelectorAll('input[data-hoster-modal]:checked'))
     .map(input => input.dataset.hosterModal);
   // Move pending files to selectedFiles on confirm
-  const pendingPaths = new Set(_pendingFiles.map(f => f.path));
-  if (_pendingFiles.length > 0) {
-    selectedFiles.push(..._pendingFiles);
-    _pendingFiles = [];
+  const admittedFiles = _pendingFiles.filter(file => window.ImportPreflight
+    .getEligibleImportHosters(file, selectedUploadHosters, hosterSettings).length > 0);
+  const pendingPaths = new Set(admittedFiles.map(f => f.path));
+  if (admittedFiles.length > 0) {
+    selectedFiles.push(...admittedFiles);
   }
+  _pendingFiles = [];
   clearDedupKeysForPaths(pendingPaths);
   renderHosterSummary();
 
@@ -1314,8 +1317,12 @@ async function applyHosterSelection() {
 }
 
 function cancelHosterModal() {
+  _importGeneration++;
+  _pendingImportInspections = 0;
+  _importCoordination = Promise.resolve();
   _pendingFiles = [];
   _pendingImportInspection = null;
+  syncImportConfirmationState();
   closeHosterModal();
 }
 
@@ -1554,6 +1561,8 @@ function setupDragDrop() {
 let _pendingFiles = []; // Files waiting for hoster modal confirmation
 let _pendingImportInspection = null;
 let _importCoordination = Promise.resolve();
+let _importGeneration = 0;
+let _pendingImportInspections = 0;
 
 let _addingDropped = false;
 
@@ -1595,13 +1604,24 @@ function getImportPlanHosters() {
     : getSelectedHosters();
 }
 
-function renderImportPlanSummary() {
-  if (!_pendingImportInspection || !window.ImportPreflight) return;
-  const summary = window.ImportPreflight.summarizeImportPlan({
+function getImportPlanSummary() {
+  if (!_pendingImportInspection || !window.ImportPreflight) return null;
+  return window.ImportPreflight.summarizeImportPlan({
     inspection: _pendingImportInspection,
     selectedHosters: getImportPlanHosters(),
     hosterSettings
   });
+}
+
+function syncImportConfirmationState() {
+  const confirmButton = document.getElementById('confirmHosterModalBtn');
+  if (confirmButton) confirmButton.disabled = _pendingImportInspections > 0;
+}
+
+function renderImportPlanSummary() {
+  const summary = getImportPlanSummary();
+  syncImportConfirmationState();
+  if (!summary) return;
   const values = {
     importPlanCandidates: summary.candidateCount,
     importPlanDuplicates: summary.duplicateCount,
@@ -1618,21 +1638,41 @@ function renderImportPlanSummary() {
   }
 }
 
+function formatRejectedImportBalance(inspection) {
+  const values = [
+    ['Kandidaten', inspection.candidateCount],
+    ['Bereits vorhanden / dupliziert', inspection.duplicateCount],
+    ['Durch Dateinamenfilter ausgeschlossen', inspection.filteredCount],
+    ['Fehlend / unlesbar / leer', inspection.unavailableCount],
+    ['Akzeptierte Dateien', inspection.acceptedCount]
+  ];
+  return values.map(([label, value]) => `${localizeUiText(label)}: ${Number(value) || 0}`).join(' · ');
+}
+
 function existingImportPaths() {
   return [...selectedFiles.map(file => file.path), ..._pendingFiles.map(file => file.path), ...queueJobs.map(job => job.file)];
 }
 
-function coordinateImportEntries(entries) {
+function coordinateImportEntries(entries, inspectEntries) {
+  const candidates = Array.isArray(entries) ? entries : [];
+  if (candidates.length === 0) return Promise.resolve(null);
+  const generation = _importGeneration;
+  _pendingImportInspections++;
+  syncImportConfirmationState();
   const run = async () => {
-    const candidates = Array.isArray(entries) ? entries : [];
-    if (candidates.length === 0) return null;
+    if (generation !== _importGeneration) return null;
     let inspection;
     try {
-      inspection = await window.api.inspectImportFiles(candidates, existingImportPaths());
+      const inspect = typeof inspectEntries === 'function'
+        ? inspectEntries
+        : (values, existingPaths) => window.api.inspectImportFiles(values, existingPaths);
+      inspection = await inspect(candidates, existingImportPaths());
     } catch {
+      if (generation !== _importGeneration) return null;
       showCopyToast('Vorabprüfung fehlgeschlagen.', 6500);
       return null;
     }
+    if (generation !== _importGeneration) return null;
     mergePendingImportInspection(inspection);
     if (inspection.accepted.length > 0) {
       if (document.getElementById('hosterModal')?.style.display === 'flex') {
@@ -1643,23 +1683,24 @@ function coordinateImportEntries(entries) {
       clearDedupKeysForPaths(acceptedPaths);
       _pendingFiles.push(...inspection.accepted);
       if (document.getElementById('hosterModal')?.style.display === 'flex') {
-        syncSelectedUploadHosters();
         renderHosterModal();
       } else {
         openHosterModal();
       }
     } else if (_pendingFiles.length > 0) {
       renderImportPlanSummary();
-    } else if (inspection.candidateCount > 0 && inspection.duplicateCount === inspection.candidateCount) {
-      showCopyToast('Auswahl ist bereits in den Upload-Aufträgen.');
-      _pendingImportInspection = null;
     } else {
-      showCopyToast('Keine Dateien wurden akzeptiert.', 6500);
+      showCopyToast(formatRejectedImportBalance(inspection), 6500);
       _pendingImportInspection = null;
     }
     return inspection;
   };
-  const pending = _importCoordination.then(run, run);
+  const operation = _importCoordination.then(run, run);
+  const pending = operation.finally(() => {
+    if (generation !== _importGeneration) return;
+    _pendingImportInspections = Math.max(0, _pendingImportInspections - 1);
+    renderImportPlanSummary();
+  });
   _importCoordination = pending.catch(() => {});
   return pending;
 }
@@ -1858,7 +1899,7 @@ function buildQueuePreview() {
     for (const file of selectedFiles) {
       for (const hoster of hosters) {
         const key = `${file.path}|${hoster}`;
-        if (!existingKeys.has(key) && !_completedUploadKeys.has(key) && !_suppressedPreviewKeys.has(key)) {
+        if (window.ImportPreflight.isImportPairEligible(file, hoster, hosterSettings) && !existingKeys.has(key) && !_completedUploadKeys.has(key) && !_suppressedPreviewKeys.has(key)) {
           const job = {
             id: `preview-${Date.now()}-${Math.random().toString(36).slice(2, 8)}`,
             file: file.path, fileName: file.name, hoster,