Migrate to import.meta.env and clean up types and eslint (#36362)

`import.meta.env` is supported in both vitest and webpack [as of
recent](https://github.com/webpack/webpack/pull/19996), so replace all
previous use of `process.env` with it. Current usage is limited to test
files, I've also verified it works in actual frontend code.

`webpack/module` is added to typescript types which includes the
definition for `import.meta.env`. I've also made the eslint globals more
precise. Finally, `__webpack_public_path__` is removed from our type
definitions because `webpack/module` also provides it.

eslint.config.ts

@@ -32,10 +32,6 @@ export default defineConfig([
     languageOptions: {
       ecmaVersion: 'latest',
       sourceType: 'module',
-      globals: {
-        ...globals.browser,
-        ...globals.node,
-      },
       parser: typescriptParser,
       parserOptions: {
         sourceType: 'module',
@@ -363,7 +359,7 @@ export default defineConfig([
       'import-x/no-self-import': [2],
       'import-x/no-unassigned-import': [0],
       'import-x/no-unresolved': [2, {commonjs: true, ignore: ['\\?.+$']}],
-      // 'import-x/no-unused-modules': [2, {unusedExports: true}], // not compatible with eslint 9
+      'import-x/no-unused-modules': [0], // incompatible with eslint 9
       'import-x/no-useless-path-segments': [2, {commonjs: true}],
       'import-x/no-webpack-loader-syntax': [2],
       'import-x/order': [0],
@@ -990,38 +986,19 @@ export default defineConfig([
       'vitest/valid-title': [2],
     },
   },
-  {
-    files: ['web_src/js/types.ts'],
-    rules: {
-      'import-x/no-unused-modules': [0],
-    },
-  },
   {
     files: ['**/*.d.ts'],
     rules: {
-      'import-x/no-unused-modules': [0],
       '@typescript-eslint/consistent-type-definitions': [0],
       '@typescript-eslint/consistent-type-imports': [0],
     },
   },
   {
-    files: ['*.config.*'],
-    rules: {
-      'import-x/no-unused-modules': [0],
-    },
+    files: ['*', 'tools/**/*'],
+    languageOptions: {globals: globals.node},
   },
   {
     files: ['web_src/**/*', 'docs/**/*'],
     languageOptions: {globals: globals.browser},
   },
-  {
-    files: ['web_src/**/*'],
-    languageOptions: {
-      globals: {
-        ...globals.browser,
-        __webpack_public_path__: true,
-        process: false, // https://github.com/webpack/webpack/issues/15833
-      },
-    },
-  },
 ]);