fix(simple-editor): sticky Step Library panel for long recipes

Reported 2026-05-20: on a 40+ step recipe (e.g. ENP-STEEL-BASIC),
scrolling down into the Selected steps pane scrolled the Step
Library off the top of the screen. Authors had to scroll back up
to grab a step, then scroll down to drop it.

Fix: position: sticky on .o_fp_library_panel, pinned to top: 1rem
(matches the editor's padding) inside the .o_fp_simple_editor
overflow container. align-items: start on the grid so the library
column doesn't stretch to match the recipe column's height
(prerequisite for sticky to behave).

The library itself can have 30+ entries (curated step kinds +
shop-defined library templates). max-height: calc(100vh - 8rem)
+ overflow-y: auto keeps it from blowing past the viewport — it
grows its own internal scrollbar instead.

Mobile (≤900px) reverts to static positioning so the stacked
layout stays sensible.

Module: fusion_plating 19.0.20.6.1 → 19.0.20.6.2.

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

fusion_plating/fusion_plating/__manifest__.py

@@ -5,7 +5,7 @@
 
 {
     'name': 'Fusion Plating',
-    'version': '19.0.20.6.1',
+    'version': '19.0.20.6.2',
     'category': 'Manufacturing/Plating',
     'summary': 'Core plating / metal finishing ERP: facilities, processes, tanks, baths, jobs, operators.',
     'description': """