Bug 38728: (follow-up) Fix cashup modal triggering after POST/REDIRECT/GET implementation

The upstream implementation of POST/REDIRECT/GET pattern for cashup operations
introduced a regression where the cashup modal would no longer auto-trigger
after successful cashup submission. The original approach passed cashup_id as
a query parameter in the redirect, but the template variable was not being
populated from the URL parameter, causing the JavaScript to receive an empty
value.

This follow-up implements a more modern and reliable solution using URL hash
fragments instead of query parameters:

1. Changed redirect URLs to use hash fragments (e.g., #cashup-123)
2. Updated JavaScript to detect and parse hash fragments on page load
3. Auto-triggers the cashup modal when hash is present
4. Cleans up the URL using history.replaceState() after modal opens

Benefits:
- Maintains proper POST/REDIRECT/GET pattern
- Hash fragments don't trigger server requests or require server-side handling
- More reliable than template variable approach
- Follows modern web development patterns
- Works consistently across both register.pl and registers.pl pages

Test plan:
1. Navigate to POS register page (pos/register.pl)
2. Perform a cashup operation
3. Verify the cashup summary modal automatically appears after redirect
4. Verify the URL is clean (no hash fragment visible)
5. Repeat for registers summary page (pos/registers.pl)
6. Perform individual register cashup
7. Verify modal auto-triggers correctly

Signed-off-by: Andrew Fuerste Henry <andrew@bywatersolutions.com>
Signed-off-by: Lucas Gass <lucas@bywatersolutions.com>

koha-tmpl/intranet-tmpl/prog/en/modules/pos/register.tt

@@ -575,12 +575,17 @@
         }, null, 1);
 
         $(document).ready(function() {
-            [% IF cashup_id %]
-            let $button = $('[data-cashup="[% cashup_id | html %]"]');
-            if ($button.length) {
-                $button[0].click();
+            // Check for cashup hash in URL
+            let hash = window.location.hash;
+            if (hash && hash.startsWith('#cashup-')) {
+                let cashup_id = hash.substring(8); // Remove '#cashup-' prefix
+                let $button = $('[data-cashup="' + cashup_id + '"]');
+                if ($button.length) {
+                    $button[0].click();
+                    // Clean up URL without page reload
+                    history.replaceState(null, null, window.location.pathname + window.location.search);
+                }
             }
-            [% END %]
         });
     </script>
 [% END %]

koha-tmpl/intranet-tmpl/prog/en/modules/pos/registers.tt

@@ -241,12 +241,17 @@
                $('#cashup_registerid').val(rid);
             });
 
-            [% IF cashup_id %]
-            let $button = $('[data-cashup="[% cashup_id | html %]"]');
-            if ($button.length) {
-                $button[0].click();
+            // Check for cashup hash in URL
+            let hash = window.location.hash;
+            if (hash && hash.startsWith('#cashup-')) {
+                let cashup_id = hash.substring(8); // Remove '#cashup-' prefix
+                let $button = $('[data-cashup="' + cashup_id + '"]');
+                if ($button.length) {
+                    $button[0].click();
+                    // Clean up URL without page reload
+                    history.replaceState(null, null, window.location.pathname + window.location.search);
+                }
             }
-            [% END %]
         });
     </script>
 [% END %]

pos/register.pl

@@ -112,7 +112,8 @@ if ( !$registers->count ) {
             );
 
             # Redirect to prevent duplicate submissions (POST/REDIRECT/GET pattern)
-            print $input->redirect( "/cgi-bin/koha/pos/register.pl?registerid=" . $registerid  . "&cashup_id=" . $cashup->id );
+            print $input->redirect(
+                "/cgi-bin/koha/pos/register.pl?registerid=" . $registerid . "#cashup-" . $cashup->id );
             exit;
         } else {
             $template->param( error_cashup_permission => 1 );

pos/registers.pl

@@ -56,16 +56,17 @@ if ( !$registers->count ) {
 my $op = $input->param('op') // '';
 if ( $op eq 'cud-cashup' ) {
     if ( $logged_in_user->has_permission( { cash_management => 'cashup' } ) ) {
-        my $registerid = $input->param('registerid');
+        my $registerid   = $input->param('registerid');
+        my $redirect_url = "/cgi-bin/koha/pos/registers.pl";
         if ($registerid) {
             my $register = Koha::Cash::Registers->find( { id => $registerid } );
-            my $cashup = $register->add_cashup(
+            my $cashup   = $register->add_cashup(
                 {
                     manager_id => $logged_in_user->id,
                     amount     => $register->outstanding_accountlines->total
                 }
             );
-            $template->param( cashup_id => $cashup->id );
+            $redirect_url .= "#cashup-" . $cashup->id;
         } else {
             for my $register ( $registers->as_list ) {
                 $register->add_cashup(
@@ -78,7 +79,7 @@ if ( $op eq 'cud-cashup' ) {
         }
 
         # Redirect to prevent duplicate submissions (POST/REDIRECT/GET pattern)
-        print $input->redirect("/cgi-bin/koha/pos/registers.pl");
+        print $input->redirect($redirect_url);
         exit;
     } else {
         $template->param( error_cashup_permission => 1 );