fix(plating): UAT-caught UX annoyances + lurking bugs

Five fixes from the end-to-end UAT debrief:

1. Menu discoverability (HIGH)
   Added a prominent "+ New Direct Order" button in the Sale Orders
   list header toolbar (class=btn-primary, display=always). The
   existing menuitem at Plating > Sales > New Direct Order was
   buried in a submenu that didn't always expand; the toolbar
   button is a guaranteed entry point from the most common screen.

2. Escape/X destroys wizard state (HIGH)
   Added a prominent info banner at the top of the wizard form:
   "Changes are not saved until you click Create & Confirm Order.
   Closing this window (Esc or X) discards your entries." The
   Cancel button now has confirm="Discard this order? All header
   data and line items will be lost." so the intentional-cancel
   path also prompts.

3. Shell/cron crash in _fp_auto_create_mo (MEDIUM)
   bridge_mrp/models/sale_order.py:232-264 used _() inside list
   comprehensions to format the internal chatter summary of newly
   created / adopted MOs. _() resolves language from env.context,
   which is empty in odoo-shell and cron contexts — triggering a
   translate.get_text_alias crash AFTER the MOs had been created.
   These strings are internal audit log text, not user-facing UI;
   dropped the _() wrappers so the message builds safely from any
   context. Same for the per-group error-message on savepoint
   rollback.

4. Misleading "100%" margin (MEDIUM)
   x_fc_margin_percent displayed 100% on every SO because the cost
   rollup from fp.coating.config.unit_cost isn't populated yet.
   Added x_fc_margin_available Boolean (True only when at least
   one line's coating has a non-zero unit_cost). The SO Plating
   tab now hides the margin numbers when margin_available=False
   and shows an inline muted note: "Margin n/a — coating cost
   rollup not yet populated on any line's treatment."

5. Account Hold banner too loud (LOW)
   fusion_plating_invoicing was injecting a full-height danger
   alert above every SO header. Slimmed it to a one-line compact
   alert with icon: "Account Hold — SO confirmation, invoicing
   and shipping are blocked for non-managers." Half the vertical
   footprint, less visual competition with the Plating chip bar.

Verified via UAT on S00071.

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

fusion_plating/fusion_plating_configurator/wizard/fp_direct_order_wizard_views.xml

@@ -6,6 +6,13 @@
         <field name="model">fp.direct.order.wizard</field>
         <field name="arch" type="xml">
             <form string="Direct Order Entry">
+                <div class="alert alert-info py-2 mb-0 small"
+                     role="alert">
+                    <i class="fa fa-info-circle me-1"/>
+                    Changes are not saved until you click
+                    <strong>Create &amp; Confirm Order</strong>. Closing this
+                    window (Esc or X) discards your entries.
+                </div>
                 <div class="alert alert-warning mb-0"
                      role="alert"
                      invisible="not missing_info_msg">
@@ -194,7 +201,10 @@
                             type="object"
                             string="Create &amp; Confirm Order"
                             class="btn-primary"/>
-                    <button string="Cancel" special="cancel" class="btn-secondary"/>
+                    <button string="Cancel"
+                            special="cancel"
+                            class="btn-secondary"
+                            confirm="Discard this order? All header data and line items will be lost."/>
                 </footer>
             </form>
         </field>