feat(pos): add plate lookup (#8), 326 translations (#12), bulk image import (#11)

- Plate lookup: new plate_vehicles table (v1.7 migration), plate_lookup
  service with Mexican plate validation, GET/POST endpoints on catalog_bp,
  plate search UI in catalog vehicle selector
- Translations: extend PART_TRANSLATIONS from ~80 to 326 entries covering
  brake, engine, fuel, cooling, electrical, drivetrain, suspension, steering,
  exhaust, A/C, lighting, body, interior, fluids, and category translations
- Bulk images: image_scraper service with download+resize+placeholder
  generation, bulk-images and auto-image endpoints on inventory_bp

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

pos/migrations/v1.7_plates.sql

@@ -0,0 +1,16 @@
+-- Plate-to-vehicle lookup table (tenant DB)
+-- Allows instant vehicle identification from Mexican license plates.
+
+CREATE TABLE IF NOT EXISTS plate_vehicles (
+    id SERIAL PRIMARY KEY,
+    plate VARCHAR(20) UNIQUE NOT NULL,
+    make VARCHAR(100),
+    model VARCHAR(100),
+    year INTEGER,
+    vin VARCHAR(17),
+    customer_id INTEGER REFERENCES customers(id),
+    created_at TIMESTAMPTZ DEFAULT NOW()
+);
+
+CREATE INDEX IF NOT EXISTS idx_plate_vehicles_plate ON plate_vehicles(plate);
+CREATE INDEX IF NOT EXISTS idx_plate_vehicles_customer ON plate_vehicles(customer_id);