fix(kanban): show horizontal scrollbar instead of wrapping columns

Salvage follow-up on top of @vynxevainglory-ai's PR #29233. Keep the
column-body flex:1 + min-height:0 fix (tall columns scroll internally
now), but drop the flex-wrap: wrap part — instead just stop hiding
the existing horizontal scrollbar.

PR #523254b34 (sadiksaifi, May 18) deliberately moved the kanban board
from a wrapping grid to a single-row pinned-width flex so the board
stays as one stable horizontal row. The mistake in that PR was the
scrollbar-width: none + ::-webkit-scrollbar { display: none } pair,
which hid the affordance so columns past the viewport became visually
inaccessible. Fixing that hidden-scrollbar bug while keeping the
single-row design honors both contributors' intent.

plugins/kanban/dashboard/dist/style.css

@@ -64,9 +64,9 @@
 
 .hermes-kanban-columns {
   display: flex;
-  flex-wrap: wrap;
   gap: 0.75rem;
   align-items: start;
+  overflow-x: auto;
 }
 
 .hermes-kanban-column {