fix: remove sticky column left border in workspace theme

Google Drive has no column separators — override Angular Material's
built-in border-left on mat-mdc-table-sticky-border-elem-right.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: renemadsen

eform-client/src/scss/components/_workspace-overrides.scss

@@ -64,6 +64,11 @@ body.theme-workspace {
     border-bottom-style: solid;
   }
 
+  // Remove sticky-column left border (Google Drive has no column separators)
+  .mat-mdc-table-sticky-border-elem-right {
+    border-left: none !important;
+  }
+
   // --- Sort header — Google Drive style ---
 
   // Hide the mtx-grid sort/filter icon (≡) only on the actively sorted column