fix(numbering): post-review fixes — credit notes, SO unlink, multi-part grouping, SQL whitelist

- B1: Add Credit Note wizard path was blocked because invoice_origin
  has copy=False and the wizard doesn't set fp_from_so_invoice. Now
  the validator allows reversals when reversed_entry_id points at a
  customer-facing move that itself went through the validator at
  original creation time. account.move._fp_parent_sale_order also
  walks self.reversed_entry_id._fp_parent_sale_order so the credit
  note inherits the parent number (CN-<parent>).

- Bug 1: sale.order.unlink() now blocks deletion when x_fc_parent_number
  is set (matches spec §6.2). Draft quotes remain freely deletable
  per Odoo standard. Applies to all users including admins.

- Bug 2: out_receipt added to CUSTOMER_TYPES so POS-style receipts
  hit the same SO-flow gate as out_invoice / out_refund.

- C1: WO grouping key changed from recipe.id to (recipe.id, part.id,
  coating.id). Bundling lines with different parts under one WO put
  first_line's part_number on the CoC header — silent compliance
  mis-attestation. Now distinct parts always get distinct WOs even
  when they share a recipe.

- C3: SQL whitelist (_FP_COUNTER_FIELD_RE) on _fp_assign_parent_name's
  interpolated counter field name. No user input today; defence in
  depth for future subclasses that might read the name from context.

Verified on entech: parent=30017, credit note = CN-30017,
multi-part SO produces 2 WOs (one per part), confirmed-SO unlink
blocked, out_receipt blocked, whitelist regex enforced.

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

fusion_plating/fusion_plating_jobs/models/sale_order.py

@@ -314,6 +314,23 @@ class SaleOrder(models.Model):
             fp_invoice_source_so_id=self.id if len(self) == 1 else False,
         ))._create_invoices(grouped=grouped, final=final, date=date)
 
+    def unlink(self):
+        """Spec §6.2 — confirmed SOs are part of the compliance audit
+        trail and cannot be deleted. Cancellation must go through the
+        state machine instead. Draft SOs (no parent_number assigned
+        yet) remain freely deletable per Odoo standard. Applies to
+        all users including administrators."""
+        for so in self:
+            if so.x_fc_parent_number:
+                raise UserError(_(
+                    'Sale Order "%(name)s" cannot be deleted — it has '
+                    'been confirmed (parent number %(parent)s issued) '
+                    'and is part of the compliance audit trail. Cancel '
+                    'it instead. This rule applies to all users '
+                    'including administrators.'
+                ) % {'name': so.display_name, 'parent': so.x_fc_parent_number})
+        return super().unlink()
+
     def _fp_resolve_recipe_for_line(self, line):
         """4-tier recipe resolution. Used BOTH for grouping (Task 6
         recipe-driven WO splits) AND for the per-job vals construction.
@@ -395,15 +412,29 @@ class SaleOrder(models.Model):
             _logger.info('SO %s: no plating lines, skipping job creation.', self.name)
             return
 
-        # Group by resolved recipe id (lines sharing a recipe → one WO).
-        # No-recipe lines get their own group each (preserves the legacy
-        # "one job per line" behaviour for unrecipe'd SOs).
+        # Group by (recipe, part, coating). Lines that share ALL THREE
+        # collapse into one WO. Sharing only the recipe is not enough —
+        # the WO header captures part_id and coating_config_id from
+        # first_line, and downstream the CoC prints the WO header's
+        # part_number on the customer-facing cert. Bundling Part A +
+        # Part B under one WO because they happen to share a recipe
+        # would put Part A's number on a cert covering both, which is
+        # a compliance bug (silent mis-attestation).
+        # No-recipe lines get their own group each.
         groups = {}
         unrecipe_idx = 0
         for line in plating_lines:
             recipe = self._fp_resolve_recipe_for_line(line)
+            part_id = (
+                'x_fc_part_catalog_id' in line._fields
+                and line.x_fc_part_catalog_id.id
+            ) or False
+            coating_id = (
+                'x_fc_coating_config_id' in line._fields
+                and line.x_fc_coating_config_id.id
+            ) or False
             if recipe:
-                key = recipe.id
+                key = (recipe.id, part_id, coating_id)
             else:
                 unrecipe_idx += 1
                 key = ('no_recipe', unrecipe_idx)