fix(shopfloor): mobile scroll works — remove nested scroll containers

User: "scrolling is not working" in Chrome DevTools mobile simulation.
Three actual problems:

1. Plant Overview columns had max-height: calc(100vh - 180px) +
   overflow: hidden, with a nested overflow-y: auto on the column
   body. Classic Trello kanban pattern — works on desktop, breaks
   on mobile. You get two scroll containers fighting each other and
   the PAGE itself can't scroll past the viewport height.

2. .o_fp_po_columns had overflow-x: auto on all widths. On the
   phone-stack breakpoint (<600px) this was also still on, creating
   another nested scroll container.

3. Draggable cards can swallow touch events on mobile because
   touch-action defaults to "auto" and Chrome's mobile simulator
   treats touch on draggable elements as potential drag-start.

Fixes — all at the <=900px breakpoint (tablets + phones):

  .o_fp_po_column          max-height: none; overflow: visible
  .o_fp_po_col_body        overflow-y: visible
  .o_fp_po_columns         flex-direction: column; overflow: visible

Plus .o_fp_po_card carries `touch-action: pan-y` unconditionally —
touch-scroll gestures never get hijacked by the draggable="true"
attribute. Desktop mousedown drag still works (HTML5 drag-drop
isn't touch-based by default).

Also added -webkit-overflow-scrolling: touch to all three page
roots (.o_fp_tablet, .o_fp_manager, .o_fp_plant_overview) and to
the internal scroll containers that remain on desktop — gives iOS
Safari proper momentum scroll (11 occurrences in the compiled
bundle).

Drag-drop JS preventDefault calls audited — they only fire on
dragover/drop (HTML5 drag events), which don't exist on touch by
default, so no touch interference there.

Verified via compiled CSS:
  .o_fp_po_card { touch-action: pan-y; ... }
  @media (max-width: 900px) .o_fp_po_column { overflow-x: visible;
         overflow-y: visible; min-height: auto }
  @media (max-width: 900px) .o_fp_po_col_body { overflow-y: visible }

Version bumped 19.0.5.0.0 -> 19.0.6.0.0 to force the bundle hash
to change. New URL: /web/assets/4a1b69e/web.assets_backend.min.css

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

fusion_plating/fusion_plating_shopfloor/__manifest__.py

@@ -5,7 +5,7 @@
 
 {
     'name': 'Fusion Plating — Shop Floor',
-    'version': '19.0.5.0.0',
+    'version': '19.0.6.0.0',
     'category': 'Manufacturing/Plating',
     'summary': 'Shop-floor tablet stations, QR scanning, bake window enforcer, '
                'first-piece inspection gates.',

fusion_plating/fusion_plating_shopfloor/static/src/scss/fusion_plating_shopfloor.scss

@@ -28,6 +28,8 @@
     display: flex;
     flex-direction: column;
     gap: $fp-space-6;
+    // Smooth momentum scroll on iOS / iPadOS Safari
+    -webkit-overflow-scrolling: touch;
 
     @media (max-width: 900px) { padding: $fp-space-4; gap: $fp-space-4; }
     @media (max-width: 600px) { padding: $fp-space-3; gap: $fp-space-4; }

fusion_plating/fusion_plating_shopfloor/static/src/scss/manager_dashboard.scss

@@ -26,6 +26,7 @@
     display: flex;
     flex-direction: column;
     gap: $fp-space-6;
+    -webkit-overflow-scrolling: touch;
 
     @media (max-width: 900px) { padding: $fp-space-4; gap: $fp-space-4; }
     @media (max-width: 600px) { padding: $fp-space-3; gap: $fp-space-4; }

fusion_plating/fusion_plating_shopfloor/static/src/scss/plant_overview.scss

@@ -23,6 +23,7 @@
     min-height: 100%;
     display: flex;
     flex-direction: column;
+    -webkit-overflow-scrolling: touch;
 }
 
 
@@ -112,13 +113,21 @@
     gap: $fp-space-4;
     padding: 0 $fp-space-6 $fp-space-6;
     overflow-x: auto;
+    -webkit-overflow-scrolling: touch;
     flex: 1;
     min-height: 0;
     align-items: flex-start;
 
-    @media (max-width: 900px) { padding: 0 $fp-space-4 $fp-space-4; }
-    @media (max-width: 600px) {
+    // Mobile: stack vertically, remove the horizontal overflow (and
+    // therefore the inner scroll trap); the page scrolls instead.
+    @media (max-width: 900px) {
         flex-direction: column;
+        overflow-x: visible;
+        overflow-y: visible;
+        min-height: auto;
+        padding: 0 $fp-space-4 $fp-space-4;
+    }
+    @media (max-width: 600px) {
         padding: 0 $fp-space-3 $fp-space-3;
     }
 }
@@ -138,10 +147,15 @@
     max-height: calc(100vh - 180px);
     overflow: hidden;
 
-    @media (max-width: 600px) {
+    // Touch / mobile: let columns be their natural height and let the
+    // PAGE scroll instead of each column having its own internal
+    // scroll. Nested scroll containers are unusable on a phone.
+    @media (max-width: 900px) {
         flex: 1 1 auto;
-        min-width: 100%; max-width: 100%;
+        min-width: 100%;
+        max-width: 100%;
         max-height: none;
+        overflow: visible;
     }
 }
 
@@ -173,9 +187,18 @@
     overflow-y: auto;
     padding: $fp-space-3;
     flex: 1;
+    // Smooth inertial scroll on iOS Safari
+    -webkit-overflow-scrolling: touch;
     transition: background-color $fp-dur $fp-ease,
                 box-shadow $fp-dur $fp-ease;
 
+    // Mobile: disable the nested overflow so the page scrolls the
+    // whole list naturally instead of trapping scroll inside each
+    // column.
+    @media (max-width: 900px) {
+        overflow-y: visible;
+    }
+
     // Drop-zone highlight: soft accent tint + inset outline. Shows the
     // whole column is receptive. The actual insertion point is drawn
     // by the real placeholder node (inserted by JS) between cards.
@@ -220,6 +243,10 @@
     margin-bottom: $fp-space-2;
     cursor: grab;
     box-shadow: $fp-elev-1;
+    // Allow vertical page-scroll gestures on touch — without this
+    // a draggable card can swallow the touch and block scrolling.
+    // Desktop drag (mousedown) still works.
+    touch-action: pan-y;
     transition: transform $fp-dur-fast $fp-ease,
                 box-shadow $fp-dur $fp-ease,
                 opacity $fp-dur $fp-ease,