feat(#19): Add filamentcolors.xyz color lookup integration

- Backend proxy endpoints: GET /filamentcolors/manufacturers, GET /filamentcolors/search
- Frontend: FilamentColorLookup modal with manufacturer filter + color search
- Color grid shows swatches with hex codes, click to apply
- Added to both filament create and edit forms next to ColorPicker

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

client/public/locales/en/common.json

@@ -362,6 +362,14 @@
         },
         "buttons": {
             "add_spool": "Add Spool"
+        },
+        "color_lookup": {
+            "button": "Find color from filamentcolors.xyz",
+            "title": "Find Color - filamentcolors.xyz",
+            "manufacturer": "Manufacturer",
+            "color_search": "Search color name...",
+            "results": "results",
+            "showing_page": "page {{page}}"
         }
     },
     "vendor": {