fusion_plating: add process recipe system with OWL tree editor (v19.0.2.0.0)

New model fusion.plating.process.node with _parent_store hierarchy for
defining reusable plating recipes. Node types: recipe, sub_process,
operation, step. Includes companion model for operator input definitions.

Full OWL tree editor (client action) with:
- Hierarchical tree with connector lines and type-coloured borders
- Click-to-edit side panel with save
- Add/delete child nodes inline
- Drag & drop reorder and reparent
- Theme-aware SCSS (light + dark mode)
- Demo data: Electroless Nickel Plating — Steel Line (30+ nodes)

Backend: 7 JSON-RPC endpoints for tree CRUD, reorder, move, duplicate.
Security: 3-tier ACL (operator read / supervisor write / manager full).
Menu: Process Recipes under Plating > Operations.

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

fusion-plating/fusion_plating/views/fp_menu.xml

@@ -19,6 +19,12 @@
               parent="menu_fp_root"
               sequence="10"/>
 
+    <menuitem id="menu_fp_process_recipes"
+              name="Process Recipes"
+              parent="menu_fp_operations"
+              action="action_fp_process_recipe"
+              sequence="5"/>
+
     <menuitem id="menu_fp_baths"
               name="Baths"
               parent="menu_fp_operations"