feat(thickness): single Char range field — drop fp.recipe.thickness picker

Per client direction: every order is a thickness RANGE (e.g.
"0.0005-0.0008 mils" or "5-10 mils"), never a single value. The
old picker model (fp.recipe.thickness with a single 'value' Float)
was modelling the wrong concept and overcrowding the order entry
UI. Replaced with one free-text Char field that auto-fills from
last-used or part default.

DELETED entirely:
- fp.recipe.thickness model (file + view + ACL + manifest entry)
- recipe.thickness_option_ids One2many (the picker source)
- "Thickness Options" inline list on the recipe form
- sale.order.line.x_fc_thickness_id (M2O picker)
- account.move.line.x_fc_thickness_id
- fp.delivery.x_fc_thickness_id
- fp.direct.order.line.thickness_id

ADDED:
- sale.order.line.x_fc_thickness_range (Char) — operator types range
- account.move.line.x_fc_thickness_range — for invoice rendering
- fp.delivery.x_fc_thickness_range — for packing slip
- fp.direct.order.line.thickness_range — for the wizard
- fp.part.catalog.x_fc_default_thickness_range — part default

AUTO-FILL CHAIN (sale.order.line + wizard line):
1. Operator already typed → keep
2. Most recent SO line for (this part, this customer) with a
   non-empty thickness_range → copy that
3. part.x_fc_default_thickness_range → copy
4. Blank — operator types

Implemented as both an @api.onchange (interactive) AND a
create() override (programmatic — wizard, sale_mrp bridge,
imports). Same logic in both paths.

WIZARD push-to-defaults: when "Save as Default" toggle is ticked
on a wizard line, persist the line's thickness_range to
part.x_fc_default_thickness_range so future first-customer orders
get a sensible starting point.

REPORTS: customer_line_header.xml + report_fp_wo_sticker.xml now
print the Char range as-typed (no display_name lookup needed).

KEPT (admin documentation only — doesn't affect order entry):
- recipe.thickness_min, thickness_max, thickness_uom on the recipe
  root: documents the recipe's CAPABILITY range. No UI gate; just
  for spec authors to record what the chemistry can produce.

JOB GROUPING: fp.job auto-create groups SO lines by (recipe, part,
spec, thickness, serial). Updated to key on the thickness_range
Char (stripped) instead of the deleted thickness_id integer.

DB cleanup: --update=base ran on the upgrade, dropping the
fp_recipe_thickness table + the four x_fc_thickness_id columns.
Existing data was already nulled in earlier dev work.

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

fusion_plating/fusion_plating/views/fp_process_node_views.xml

@@ -255,18 +255,14 @@
                                 <field name="is_locked" widget="boolean_toggle"
                                        help="When ON, only managers can edit this recipe and its child operations / steps. Use for NADCAP-qualified processes."/>
                             </group>
-                            <group string="Thickness Options">
-                                <field name="thickness_option_ids" nolabel="1">
-                                    <list editable="bottom">
-                                        <field name="sequence" widget="handle"/>
-                                        <field name="value"/>
-                                        <field name="uom"/>
-                                        <field name="label" readonly="1"/>
-                                        <field name="note" optional="hide"/>
-                                        <field name="active" optional="hide"/>
-                                    </list>
-                                </field>
-                            </group>
+                            <!-- Thickness Options group removed. The
+                                 fp.recipe.thickness picker model was
+                                 retired in favour of a single free-text
+                                 thickness range field on the SO line.
+                                 Recipe still carries thickness_min /
+                                 thickness_max above as documentation
+                                 of the recipe's capability range. -->
+
                             <!-- Applicable Specifications group is added
                                  by fusion_plating_quality via an inherit
                                  view (the field lives there too). -->

fusion_plating/fusion_plating/views/fp_recipe_thickness_views.xml

@@ -1,25 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<!--
-    Copyright 2026 Nexa Systems Inc.
-    License OPL-1 (Odoo Proprietary License v1.0)
-    Part of the Fusion Plating product family.
--->
-<odoo>
-
-    <record id="view_fp_recipe_thickness_list" model="ir.ui.view">
-        <field name="name">fp.recipe.thickness.list</field>
-        <field name="model">fp.recipe.thickness</field>
-        <field name="arch" type="xml">
-            <list string="Thickness Options" decoration-muted="not active" editable="bottom">
-                <field name="sequence" widget="handle"/>
-                <field name="recipe_id"/>
-                <field name="value"/>
-                <field name="uom"/>
-                <field name="label" string="Display"/>
-                <field name="note" optional="hide"/>
-                <field name="active" optional="hide"/>
-            </list>
-        </field>
-    </record>
-
-</odoo>