Add knip for detecting unused files and dependencies (#444)

- Add knip devDependency and lint script
- Remove unused devDependencies: @microsoft/api-extractor, cpy-cli, resolve-from, rimraf
- Update copy-licenses.js exclude list

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

Author: Boshen

knip.json

@@ -0,0 +1,31 @@
+{
+  "$schema": "https://unpkg.com/knip@5/schema.json",
+  "entry": ["scripts/*.js"],
+  "project": ["src/**/*.ts", "scripts/**/*.js", "tests/**/*.ts"],
+  "ignore": ["src/**/*.d.ts", "tests/fixtures/**"],
+  "ignoreDependencies": [
+    "@ianvs/prettier-plugin-sort-imports",
+    "@prettier/plugin-hermes",
+    "@prettier/plugin-pug",
+    "@shopify/prettier-plugin-liquid",
+    "@trivago/prettier-plugin-sort-imports",
+    "@zackad/prettier-plugin-twig",
+    "prettier-plugin-astro",
+    "prettier-plugin-css-order",
+    "prettier-plugin-jsdoc",
+    "prettier-plugin-marko",
+    "prettier-plugin-multiline-arrays",
+    "prettier-plugin-organize-attributes",
+    "prettier-plugin-organize-imports",
+    "prettier-plugin-sort-imports",
+    "prettier-plugin-svelte",
+    "import-sort-style-module",
+    "marko",
+    "postcss",
+    "postcss-import"
+  ],
+  "rules": {
+    "exports": "off",
+    "types": "off"
+  }
+}

package.json

@@ -36,14 +36,14 @@
     "test": "vitest",
     "prepublishOnly": "npm run build && node scripts/copy-licenses.js",
     "format": "prettier \"src/**/*.ts\" \"scripts/**/*.js\" \"tests/*.ts\" --write --print-width 100 --single-quote --no-semi",
+    "lint": "knip",
     "release-channel": "node ./scripts/release-channel.js",
     "release-notes": "node ./scripts/release-notes.js"
   },
   "devDependencies": {
     "@babel/types": "^7.28.2",
     "@ianvs/prettier-plugin-sort-imports": "^4.7.0",
     "@marko/compiler": "^5.39.49",
-    "@microsoft/api-extractor": "^7.52.10",
     "@prettier/plugin-hermes": "^0.1.2",
     "@prettier/plugin-oxc": "^0.1.2",
     "@prettier/plugin-pug": "^3.4.2",
@@ -52,13 +52,13 @@
     "@types/node": "^24.3.0",
     "@zackad/prettier-plugin-twig": "^0.16.0",
     "clear-module": "^4.1.2",
-    "cpy-cli": "^6.0.0",
     "dedent": "^1.6.0",
     "enhanced-resolve": "^5.18.3",
     "escalade": "^3.2.0",
     "fast-glob": "^3.3.3",
     "import-sort-style-module": "^6.0.0",
     "jiti": "^2.6.0",
+    "knip": "^5.83.0",
     "license-checker": "^25.0.1",
     "line-column": "^1.0.2",
     "marko": "^5.37.46",
@@ -75,8 +75,6 @@
     "prettier-plugin-sort-imports": "^1.8.8",
     "prettier-plugin-svelte": "^3.4.0",
     "pug-lexer": "^5.0.1",
-    "resolve-from": "^5.0.0",
-    "rimraf": "^6.0.1",
     "svelte": "^5.38.2",
     "tailwindcss-v3": "npm:tailwindcss@^3.4.18",
     "tailwindcss-v4": "npm:tailwindcss@^4.1.14",