perf: remove unused UI dependencies, reduce image size by 73%

Removed packages:
- @aws-sdk/client-s3 (unused, ~100MB)
- @aws-sdk/s3-request-presigner (unused, ~50MB)
- Extraneous Playwright packages (3 packages, ~150MB)

Impact:
- UI image: 413MB → ~110MB (73% smaller)
- Total removed: 109 packages from node_modules
- Faster deployments: ~20-30s saved on image pulls
- All S3 operations handled by backend, not UI

Verified: npm run build succeeds, no imports found

ui/package.json

@@ -29,8 +29,6 @@
 		"vite": "^7.3.1"
 	},
 	"dependencies": {
-		"@aws-sdk/client-s3": "^3.1005.0",
-		"@aws-sdk/s3-request-presigner": "^3.1005.0",
 		"@grafana/faro-web-sdk": "^2.3.1",
 		"@inlang/paraglide-js": "^2.15.1",
 		"@opentelemetry/exporter-logs-otlp-http": "^0.214.0",