Re-add SWC dependencies - required by Shakapacker 9.0 default config

Shakapacker 9.0 defaults to using SWC as the JavaScript transpiler, not Babel.
The previous commit incorrectly removed @swc/core and swc-loader, causing
webpack builds to fail with "swc-loader package is not installed" error.

Changes:
- Add back @swc/core and swc-loader to spec/dummy/package.json
- Update knip.ts to ignore SWC dependencies (not detected by Knip webpack plugin)

Note: Babel is still used for Jest tests via babel.config.js, while SWC is
used for webpack builds. This is the default Shakapacker 9.0 configuration.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

Author: justin808

knip.ts

@@ -113,6 +113,9 @@ const config: KnipConfig = {
         // Build-time dependencies not detected by Knip in any mode
         '@babel/runtime',
         'mini-css-extract-plugin',
+        // SWC dependencies used by Shakapacker 9.0 (default transpiler)
+        '@swc/core',
+        'swc-loader',
         // There's no ReScript plugin for Knip
         '@rescript/react',
         // The Babel plugin fails to detect it

spec/dummy/package.json

@@ -29,6 +29,7 @@
     "regenerator-runtime": "^0.13.4"
   },
   "devDependencies": {
+    "@swc/core": "^1.7.0",
     "@babel/core": "7.17.9",
     "@babel/plugin-transform-runtime": "7.17.0",
     "@babel/preset-env": "7",
@@ -53,6 +54,7 @@
     "sass-resources-loader": "^2.1.0",
     "shakapacker": "9.0.0",
     "style-loader": "^3.3.1",
+    "swc-loader": "^0.2.6",
     "terser-webpack-plugin": "5.3.1",
     "url-loader": "^4.0.0",
     "webpack": "5.72.0",

spec/dummy/yarn.lock

@@ -1362,6 +1362,87 @@
   dependencies:
     "@sinonjs/commons" "^3.0.0"
 
+"@swc/core-darwin-arm64@1.15.0":
+  version "1.15.0"
+  resolved "https://registry.npmjs.org/@swc/core-darwin-arm64/-/core-darwin-arm64-1.15.0.tgz#158a0890fb2546b4d57b99234c1033e4a38b62e2"
+  integrity sha512-TBKWkbnShnEjlIbO4/gfsrIgAqHBVqgPWLbWmPdZ80bF393yJcLgkrb7bZEnJs6FCbSSuGwZv2rx1jDR2zo6YA==
+
+"@swc/core-darwin-x64@1.15.0":
+  version "1.15.0"
+  resolved "https://registry.npmjs.org/@swc/core-darwin-x64/-/core-darwin-x64-1.15.0.tgz#d03a71e60244f19ac921bf23c2cafc4122d76d8e"
+  integrity sha512-f5JKL1v1H56CIZc1pVn4RGPOfnWqPwmuHdpf4wesvXunF1Bx85YgcspW5YxwqG5J9g3nPU610UFuExJXVUzOiQ==
+
+"@swc/core-linux-arm-gnueabihf@1.15.0":
+  version "1.15.0"
+  resolved "https://registry.npmjs.org/@swc/core-linux-arm-gnueabihf/-/core-linux-arm-gnueabihf-1.15.0.tgz#fe978712a8924c0555c6b248ad3b57912ba123fb"
+  integrity sha512-duK6nG+WyuunnfsfiTUQdzC9Fk8cyDLqT9zyXvY2i2YgDu5+BH5W6wM5O4mDNCU5MocyB/SuF5YDF7XySnowiQ==
+
+"@swc/core-linux-arm64-gnu@1.15.0":
+  version "1.15.0"
+  resolved "https://registry.npmjs.org/@swc/core-linux-arm64-gnu/-/core-linux-arm64-gnu-1.15.0.tgz#a5dacdd857dec4ac2931820def17bc0e42c88ede"
+  integrity sha512-ITe9iDtTRXM98B91rvyPP6qDVbhUBnmA/j4UxrHlMQ0RlwpqTjfZYZkD0uclOxSZ6qIrOj/X5CaoJlDUuQ0+Cw==
+
+"@swc/core-linux-arm64-musl@1.15.0":
+  version "1.15.0"
+  resolved "https://registry.npmjs.org/@swc/core-linux-arm64-musl/-/core-linux-arm64-musl-1.15.0.tgz#243643a7d22c8e2f334046c1d76f342ad4369be9"
+  integrity sha512-Q5ldc2bzriuzYEoAuqJ9Vr3FyZhakk5hiwDbniZ8tlEXpbjBhbOleGf9/gkhLaouDnkNUEazFW9mtqwUTRdh7Q==
+
+"@swc/core-linux-x64-gnu@1.15.0":
+  version "1.15.0"
+  resolved "https://registry.npmjs.org/@swc/core-linux-x64-gnu/-/core-linux-x64-gnu-1.15.0.tgz#26936f55c916f65d33a4cf957c7573722f9eca54"
+  integrity sha512-pY4is+jEpOxlYCSnI+7N8Oxbap9TmTz5YT84tUvRTlOlTBwFAUlWFCX0FRwWJlsfP0TxbqhIe8dNNzlsEmJbXQ==
+
+"@swc/core-linux-x64-musl@1.15.0":
+  version "1.15.0"
+  resolved "https://registry.npmjs.org/@swc/core-linux-x64-musl/-/core-linux-x64-musl-1.15.0.tgz#a7164c11ac86ed99a1d5d8bef86ec0fbe6235f6c"
+  integrity sha512-zYEt5eT8y8RUpoe7t5pjpoOdGu+/gSTExj8PV86efhj6ugB3bPlj3Y85ogdW3WMVXr4NvwqvzdaYGCZfXzSyVg==
+
+"@swc/core-win32-arm64-msvc@1.15.0":
+  version "1.15.0"
+  resolved "https://registry.npmjs.org/@swc/core-win32-arm64-msvc/-/core-win32-arm64-msvc-1.15.0.tgz#645fe54564eab4224127672f2f4fe44876223af0"
+  integrity sha512-zC1rmOgFH5v2BCbByOazEqs0aRNpTdLRchDExfcCfgKgeaD+IdpUOqp7i3VG1YzkcnbuZjMlXfM0ugpt+CddoA==
+
+"@swc/core-win32-ia32-msvc@1.15.0":
+  version "1.15.0"
+  resolved "https://registry.npmjs.org/@swc/core-win32-ia32-msvc/-/core-win32-ia32-msvc-1.15.0.tgz#fd70c8c8b542a52a88cda758fb82569d52ea949a"
+  integrity sha512-7t9U9KwMwQblkdJIH+zX1V4q1o3o41i0HNO+VlnAHT5o+5qHJ963PHKJ/pX3P2UlZnBCY465orJuflAN4rAP9A==
+
+"@swc/core-win32-x64-msvc@1.15.0":
+  version "1.15.0"
+  resolved "https://registry.npmjs.org/@swc/core-win32-x64-msvc/-/core-win32-x64-msvc-1.15.0.tgz#1d4f06078c7dbf757c537dd08740472694257198"
+  integrity sha512-VE0Zod5vcs8iMLT64m5QS1DlTMXJFI/qSgtMDRx8rtZrnjt6/9NW8XUaiPJuRu8GluEO1hmHoyf1qlbY19gGSQ==
+
+"@swc/core@^1.7.0":
+  version "1.15.0"
+  resolved "https://registry.npmjs.org/@swc/core/-/core-1.15.0.tgz#6ae4dbd5a164261ba799ccdf9eae3bbc61e112c2"
+  integrity sha512-8SnJV+JV0rYbfSiEiUvYOmf62E7QwsEG+aZueqSlKoxFt0pw333+bgZSQXGUV6etXU88nxur0afVMaINujBMSw==
+  dependencies:
+    "@swc/counter" "^0.1.3"
+    "@swc/types" "^0.1.25"
+  optionalDependencies:
+    "@swc/core-darwin-arm64" "1.15.0"
+    "@swc/core-darwin-x64" "1.15.0"
+    "@swc/core-linux-arm-gnueabihf" "1.15.0"
+    "@swc/core-linux-arm64-gnu" "1.15.0"
+    "@swc/core-linux-arm64-musl" "1.15.0"
+    "@swc/core-linux-x64-gnu" "1.15.0"
+    "@swc/core-linux-x64-musl" "1.15.0"
+    "@swc/core-win32-arm64-msvc" "1.15.0"
+    "@swc/core-win32-ia32-msvc" "1.15.0"
+    "@swc/core-win32-x64-msvc" "1.15.0"
+
+"@swc/counter@^0.1.3":
+  version "0.1.3"
+  resolved "https://registry.npmjs.org/@swc/counter/-/counter-0.1.3.tgz#cc7463bd02949611c6329596fccd2b0ec782b0e9"
+  integrity sha512-e2BR4lsJkkRlKZ/qCHPw9ZaSxc0MVUd7gtbtaB7aMvHeJVYe8sOB8DBZkP2DtISHGSku9sCK6T6cnY0CtXrOCQ==
+
+"@swc/types@^0.1.25":
+  version "0.1.25"
+  resolved "https://registry.npmjs.org/@swc/types/-/types-0.1.25.tgz#b517b2a60feb37dd933e542d93093719e4cf1078"
+  integrity sha512-iAoY/qRhNH8a/hBvm3zKj9qQ4oc2+3w1unPJa2XvTK3XjeLXtzcCingVPw/9e5mn1+0yPqxcBGp9Jf0pkfMb1g==
+  dependencies:
+    "@swc/counter" "^0.1.3"
+
 "@types/babel__core@^7.1.14":
   version "7.20.5"
   resolved "https://registry.yarnpkg.com/@types/babel__core/-/babel__core-7.20.5.tgz#3df15f27ba85319caa07ba08d0721889bb39c017"
@@ -5967,6 +6048,13 @@ supports-preserve-symlinks-flag@^1.0.0:
   resolved "https://registry.yarnpkg.com/supports-preserve-symlinks-flag/-/supports-preserve-symlinks-flag-1.0.0.tgz#6eda4bd344a3c94aea376d4cc31bc77311039e09"
   integrity sha512-ot0WnXS9fgdkgIcePe6RHNk1WA8+muPa6cSjeR3V8K27q9BB1rTE3R1p7Hv0z1ZyAc8s6Vvv8DIyWf681MAt0w==
 
+swc-loader@^0.2.6:
+  version "0.2.6"
+  resolved "https://registry.npmjs.org/swc-loader/-/swc-loader-0.2.6.tgz#bf0cba8eeff34bb19620ead81d1277fefaec6bc8"
+  integrity sha512-9Zi9UP2YmDpgmQVbyOPJClY0dwf58JDyDMQ7uRc4krmc72twNI2fvlBWHLqVekBpPc7h5NJkGVT1zNDxFrqhvg==
+  dependencies:
+    "@swc/counter" "^0.1.3"
+
 symbol-observable@^1.2.0:
   version "1.2.0"
   resolved "https://registry.yarnpkg.com/symbol-observable/-/symbol-observable-1.2.0.tgz#c22688aed4eab3cdc2dfeacbb561660560a00804"