feat(configurator): Part cell rows 2-3 now editable — type to save

Customer feedback: rows 2 (description) and 3 (serials) in the Part
cell rendered as read-only spans. User wanted to edit directly.

New writable computed fields on fp.direct.order.line:
- part_name_editable: compute reads part_catalog_id.name, inverse
  writes back to part.name on the linked catalog record
- serials_text: compute joins serial_ids names with commas; inverse
  parses the typed string and find-or-creates fp.serial records,
  updates the line's serial_ids M2M

Removed the redundant rev separator (display_name already includes
'(Rev X)' so showing it twice was clutter). Rev edits happen by
editing the part record directly via the OPEN button.

OWL widget templates updated:
- Row 2: <input> bound to part_name_editable, t-on-change saves
- Row 3: <input> bound to serials_text, t-on-change parses + saves

SCSS:
- Row 2 input: italic, transparent border, focus tints background yellow
- Row 3 input: small grey text, comma-separated friendly placeholder
- Both disabled-look when no part is picked

Both inputs trigger the inverse method on blur. The G4 sync chain
takes over from there to push line.line_description etc. back to
the part as before — so editing in the line keeps the part defaults
fresh for future orders.

fusion_plating/fusion_plating_configurator/static/src/xml/express_part_cell.xml

@@ -1,27 +1,39 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <templates xml:space="preserve">
 
-<!-- Express Orders — Part cell template (3-row stacked) -->
+<!-- Express Orders — Part cell template (3 stacked rows)
+
+     Row 1: Part picker (Many2OneField — display_name is just the
+            part_number when fp_express_part_picker context is set)
+     Row 2: editable part description (writes to part.name on blur)
+     Row 3: editable serial #s (parses comma-separated, creates fp.serial
+            records as needed) + small + bulk button
+-->
 <t t-name="fusion_plating_configurator.FpExpressPartCell">
     <div class="o_fp_xpr_part_cell">
-        <!-- Row 1: Part Number picker + Revision -->
+        <!-- Row 1 — Part picker -->
         <div class="o_fp_xpr_part_row o_fp_xpr_part_id">
             <Many2OneField t-props="props"/>
-            <span class="o_fp_xpr_part_sep">/</span>
-            <span class="o_fp_xpr_part_rev"
-                  t-esc="partRev or ''"
-                  t-att-class="{ 'o_fp_xpr_part_rev_empty': !partRev }"/>
         </div>
-        <!-- Row 2: Part description / name (italic, muted) -->
-        <div class="o_fp_xpr_part_row o_fp_xpr_part_name"
-             t-att-class="{ 'o_fp_xpr_part_name_empty': !partName }">
-            <t t-esc="partName or '— no description —'"/>
+        <!-- Row 2 — Editable part description (saves to part.name) -->
+        <div class="o_fp_xpr_part_row o_fp_xpr_part_name">
+            <input class="o_fp_xpr_part_name_input"
+                   type="text"
+                   t-att-value="partName"
+                   t-att-disabled="!hasPart"
+                   t-on-change="onNameChange"
+                   placeholder="— part description —"
+                   title="Edit the part's name — saves to the part record"/>
         </div>
-        <!-- Row 3: Serial #(s) + bulk button -->
+        <!-- Row 3 — Editable serial list + bulk-add button -->
         <div class="o_fp_xpr_part_row o_fp_xpr_part_serial">
-            <span class="o_fp_xpr_serials"
-                  t-att-class="{ 'o_fp_xpr_serials_empty': !serialsList.length }"
-                  t-esc="serialsDisplay or 'no serials yet'"/>
+            <input class="o_fp_xpr_serial_input"
+                   type="text"
+                   t-att-value="serialsText"
+                   t-att-disabled="!hasPart"
+                   t-on-change="onSerialsChange"
+                   placeholder="serial #(s) — comma separated"
+                   title="Type serials separated by commas — creates fp.serial records as needed"/>
             <button class="o_fp_xpr_bulk_btn"
                     t-on-click="onBulkClick"
                     t-att-disabled="!hasPart"