feat(configurator): drop legacy description column after dual-field migration (Sub 2 Task 27)

Removes the `description` field from `fp.sale.description.template` now
that all readers (reports, wizard, sale line) consume the new
`internal_description` + `customer_facing_description` pair.

- Model: drop `description = fields.Text(...)` declaration
- Migration 19.0.9.0.0 Step 6: `ALTER TABLE ... DROP COLUMN IF EXISTS description`
- Template form/search views: swap `description` for the two new fields
- Seed data: write new fields instead of legacy column (dupes old text into both)
- Direct-order wizard: remove `tpl.description` fallback in both onchange handlers

Entech column dropped via Odoo's auto-schema-sync during module upgrade
(migration step is for fresh installs).

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

fusion_plating/fusion_plating_configurator/models/fp_sale_description_template.py

@@ -30,14 +30,9 @@ class FpSaleDescriptionTemplate(models.Model):
         string='Template Name', required=True,
         help='Short name shown in the picker (e.g. "Standard masking", "With threaded holes masked").',
     )
-    description = fields.Text(
-        string='Description', required=True,
-        help='Boilerplate text. The user can tweak this in the wizard before '
-             'it lands on the order line.',
-    )
-    # Sub 2 — dual descriptions. Added alongside the legacy `description`
-    # field; migration copies old value into both, then old column dropped
-    # in Phase C. Nullable during Phase A so existing records don't fail.
+    # Sub 2 — dual descriptions. Replaces the legacy `description` field
+    # (dropped in Phase C / Task 27). Migration Step 3 duplicated the old
+    # value into both columns; Step 6 drops the old column.
     internal_description = fields.Text(
         string='Internal Description',
         required=True,