fix(configurator): part-level saved descriptions (not generic)

The earlier description templates were global — same 8 generic texts
applied to any part. That's useless when a customer has 3,500 parts
and each part has 3–5 canned variants (standard, masked threads,
masked bore, rework, rush packaging). That's ~17,500 rows total, and
the variants ONLY make sense in the context of a specific part number.

Restructured so descriptions live on each part:

Model changes:
  fp.sale.description.template.part_catalog_id (new M2O, indexed,
    ondelete cascade) — the primary scoping field
  fp.sale.description.template.partner_id — now a related store=True
    field pulled from the part, so customer-level search still works
  fp.part.catalog.description_template_ids (new O2M inverse) — the
    5–10 canned descriptions attached to this specific part
  fp.part.catalog.description_template_count (computed)

UI changes:
  Part Catalog form: new "Descriptions" notebook page with inline
    editable list (sequence + name + tag + description + usage_count).
    5 variants take 30 seconds to enter.
  Part Catalog form: new smart button "Descriptions" showing the count,
    jumps to the full list filtered by this part.
  Template list view: part_catalog_id column added, list ordered by
    part first. Search view adds Part filter + Part-Specific /
    Generic (No Part) filters + Group By Part.

Wizard changes:
  description_template_id domain now prioritises part-specific, falls
    through to partner, coating, or generic on a single dynamic domain.
  _onchange_suggest_template priority: part → customer → coating →
    none. No longer auto-picks a random global template when a part
    has its own.

Smoke-tested on VS-HSA201-B (Amphenol):
  5 canned variants seeded on the part form
  Wizard with this part auto-suggested the lowest-sequence one
  The part's Descriptions smart button shows "5"

Bulk data entry path for the client's 3,500 parts: either use the
inline list on each part form, or import via CSV with the new
part_catalog_id column (external_id or DB id).

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

fusion_plating/fusion_plating_configurator/wizard/fp_direct_order_wizard.py

@@ -94,12 +94,20 @@ class FpDirectOrderWizard(models.TransientModel):
 
     notes = fields.Text(string='Internal Notes')
 
-    # Description template picker (searchable / ajax-like via Odoo Many2one)
+    # Description template picker — the domain is dynamically narrowed to
+    # this part's canned descriptions first. When no part is chosen it
+    # falls through to generic templates.
     description_template_id = fields.Many2one(
         'fp.sale.description.template',
         string='Description Template',
-        help='Pick a saved boilerplate description and tweak it below. '
-             'The final text lands on the sale order line.',
+        domain="[('active','=',True), "
+               " '|', '|', '|', "
+               "   ('part_catalog_id','=',part_catalog_id), "
+               "   ('part_catalog_id','=',False), "
+               "   ('partner_id','=',partner_id), "
+               "   ('coating_config_id','=',coating_config_id)]",
+        help='Pick a saved description and tweak it below. Part-specific '
+             'descriptions appear first, then customer / coating / generic.',
     )
     line_description = fields.Text(
         string='Line Description',
@@ -126,28 +134,55 @@ class FpDirectOrderWizard(models.TransientModel):
         if self.description_template_id:
             self.line_description = self.description_template_id.description
 
-    @api.onchange('coating_config_id', 'partner_id')
+    @api.onchange('part_catalog_id', 'coating_config_id', 'partner_id')
     def _onchange_suggest_template(self):
-        """Offer a sensible default template based on coating + customer."""
+        """Offer a sensible default template — part-specific wins.
+
+        Priority (first non-empty result wins):
+          1. This part's lowest-sequence active template
+          2. This customer's templates (no part)
+          3. This coating's templates (no part)
+          4. Don't auto-pick — user has to choose
+        """
         if self.description_template_id or self.line_description:
             return  # respect user's choice
-        if not self.coating_config_id:
-            return
         Template = self.env['fp.sale.description.template']
-        # Prefer customer+coating match, then coating-only
-        match = Template.search([
-            ('active', '=', True),
-            ('partner_id', '=', self.partner_id.id if self.partner_id else False),
-            ('coating_config_id', '=', self.coating_config_id.id),
-        ], limit=1)
-        if not match:
+
+        # 1. Part-specific
+        if self.part_catalog_id:
             match = Template.search([
                 ('active', '=', True),
+                ('part_catalog_id', '=', self.part_catalog_id.id),
+            ], order='sequence', limit=1)
+            if match:
+                self.description_template_id = match.id
+                self.line_description = match.description
+                return
+
+        # 2. Customer (no part)
+        if self.partner_id:
+            match = Template.search([
+                ('active', '=', True),
+                ('part_catalog_id', '=', False),
+                ('partner_id', '=', self.partner_id.id),
+            ], order='sequence', limit=1)
+            if match:
+                self.description_template_id = match.id
+                self.line_description = match.description
+                return
+
+        # 3. Coating (no part, no customer restriction)
+        if self.coating_config_id:
+            match = Template.search([
+                ('active', '=', True),
+                ('part_catalog_id', '=', False),
+                ('partner_id', '=', False),
                 ('coating_config_id', '=', self.coating_config_id.id),
-            ], limit=1)
-        if match:
-            self.description_template_id = match.id
-            self.line_description = match.description
+            ], order='sequence', limit=1)
+            if match:
+                self.description_template_id = match.id
+                self.line_description = match.description
+                return
 
     @api.onchange('coating_config_id', 'quantity', 'partner_id')
     def _onchange_lookup_price(self):