Refactor document name sanitization for consistent filename generation

- Introduced FdsDocumentNames class to centralize the logic for sanitizing document names used in downloads.
- Updated FdsMfr to utilize the new SafeFileName method for generating safe filenames.
- Enhanced documentation for FdsDocumentNames and its methods to clarify usage and purpose.
- Added global.json file to configure testing framework settings.

Fuchs/wwwroot/web/fis.inv.de.js

@@ -162,6 +162,7 @@ let $ict = {
     pna: 'Diese Seite ist in der Vorschau nicht verfügbar',
     tpe: 'Die Anzahl von {0} Seiten wird aktuell nicht unterstützt',
     eis: 'Der Rechnungsentwurf konnte nicht gespeichert werden.',
+    pvw: 'Das Dokument wird abgerufen und für die Vorschau aufbereitet.\nDer Vorgang kann bis zu 2 Minuten dauern.',
     pvf: 'Die PDF-Vorschau konnte nicht erstellt werden.',
     pvto: 'Der Server hat nicht rechtzeitig geantwortet (Zeitüberschreitung). Bitte versuchen Sie es erneut.',
     pvgone: 'Der Entwurf ist auf dem Server nicht mehr vorhanden (Sitzung abgelaufen). Bitte öffnen Sie den Entwurf erneut.',
@@ -712,13 +713,27 @@ $inv.pdfPreviewFailed = function (jqXHR, textStatus) {
     alert(($ict.pvf || $t.f1) + (desc !== '' ? '\n' + desc : ''));
 };
 /* postXT never calls `error` for a timeout (it returns early), so the timeout is only
-   observable from `complete`; this builds the complete handler for a preview call. */
-$inv.pdfPreviewComplete = function (layout) {
+   observable from `complete`; this builds the complete handler for a preview call.
+   `wait`, if given, is the "please wait" popup from `$inv.pdfWaitDlg` — it must close on
+   every outcome (success, error, timeout), so `complete` is the only place that reliably
+   covers all three. */
+$inv.pdfPreviewComplete = function (layout, wait) {
     return (jqXHR, textStatus) => {
+        if (wait) { wait.c.trigger('modal_close'); }
         if (layout) { layout.rC('freeze'); }
         if (textStatus === 'timeout') { $inv.pdfPreviewFailed(jqXHR, textStatus); }
     };
 };
+/* A preview render can take anywhere from a couple of seconds to the full 120s timeout (a
+   cold miss regenerates + stores the PDF before rasterising it, ADR 0025); postXT's generic
+   `body.ldng` class has no CSS behind it, so nothing tells the user the click was received.
+   Same popup the MFR data fetch shows (see $inv.cInv2): spinner frame in a modal with the
+   explanation in the footer. Non-exclusive so it can sit on top of an open editor. */
+$inv.pdfWaitDlg = function () {
+    let o = $ocms.dlg($$.dc('rfrm').ldng(1), { exclusive: false, zindex_min: 50 });
+    if (o) { o.ft.rwText($ict.pvw); }
+    return o;
+};
 /* ── Backend-authoritative draft editing controller (ADR 0006/0007) ───────────
    The server holds the truth for an invoice draft in an in-memory session; this
    object seeds it, sends single edits as deltas, and renders the totals footer +
@@ -2142,6 +2157,7 @@ $inv.disp = (id, typ) => {
             break;
     }
     if (u !== '') {
+        let wait = $inv.pdfWaitDlg();
         $ocms.postXT({
             url: $ocms.url(u), data: { id: id || '', typ: 'img' }, timeout: $inv.pdfPreviewTimeout, success: (response) => {
                 let c = $$.dc('imagecollection pdfpreview'), vhr = Math.round(vh() * 0.88), invid = response.id;
@@ -2151,11 +2167,12 @@ $inv.disp = (id, typ) => {
                 $ocms.dlg(c, {
                     size: [vhr, Math.round(vw() * 0.88)], zindex_min: 50, form: false, exclusive:false
                 });
-            }, error: $inv.pdfPreviewFailed, complete: $inv.pdfPreviewComplete()
+            }, error: $inv.pdfPreviewFailed, complete: $inv.pdfPreviewComplete(null, wait)
         });
     }
 };
 $inv.jdbn = function (ev) {
+    let wait = $inv.pdfWaitDlg();
     $ocms.postXT({
         url: $ocms.url('inv/rdocn'), data: { name: ev.data.id || '', typ: 'img' }, timeout: $inv.pdfPreviewTimeout, success: (response) => {
             let c = $$.dc('imagecollection pdfpreview'), vhr = Math.round(vh() * 0.88), invid = response.id;
@@ -2165,7 +2182,7 @@ $inv.jdbn = function (ev) {
             $ocms.dlg(c, {
                 size: [vhr, Math.round(vw() * 0.88)], zindex: 50, form: false
             });
-        }, error: $inv.pdfPreviewFailed, complete: $inv.pdfPreviewComplete()
+        }, error: $inv.pdfPreviewFailed, complete: $inv.pdfPreviewComplete(null, wait)
     });
 };
 $inv.sp13b = () => {