feat(portal): customer configurator wizard — upload, coating, estimate, submit

Three-step self-service quoting flow on the customer portal:
- Step 1: Upload part (STL/PDF) or enter manual measurements + material
- Step 2: Select coating config from card grid with specs and thickness
- Step 3: View estimated price range and submit quote request

Adds dependency on fusion_plating_configurator for fp.coating.config
and fp.pricing.rule models. Price estimation uses the same rule-matching
logic as the backend configurator with a +/-15-25% range.

Dashboard updated with prominent "Get a Quote" button and portal sidebar
entry. Breadcrumbs added for configurator pages.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

fusion-plating/fusion_plating_portal/controllers/__init__.py

@@ -4,3 +4,4 @@
 # Part of the Fusion Plating product family.
 
 from . import portal
+from . import portal_configurator