fix(ses): fix broken types for CJS consumers

Due to changes in TS v5.5, CJS consumers cannot import types from a `type: module` package unless the declaration file has the `.d.cts` extension.  This may or may not work the other way.

See https://devblogs.microsoft.com/typescript/announcing-typescript-5-5-beta/\#respecting-file-extensions-and-packagejson-in-other-module-modes for explanation.

packages/ses/package.json

@@ -35,15 +35,25 @@
   "unpkg": "./dist/ses.umd.js",
   "types": "./types.d.ts",
   "exports": {
-    ".": {
-      "types": "./types.d.ts",
-      "import": "./index.js",
-      "require": "./dist/ses.cjs"
+    ".": {      
+      "import": {
+        "types": "./types.d.ts",
+        "default": "./index.js"
+      },
+      "require": {
+        "types": "./dist/types.d.cts",
+        "default": "./dist/ses.cjs"
+      }
     },
-    "./lockdown": {
-      "types": "./types.d.ts",
-      "import": "./index.js",
-      "require": "./dist/ses.cjs"
+    "./lockdown": {      
+      "import": {
+        "types": "./types.d.ts",
+        "default": "./index.js"
+      },
+      "require": {
+        "types": "./dist/types.d.cts",
+        "default": "./dist/ses.cjs"
+      }
     },
     "./tools.js": "./tools.js",
     "./assert-shim.js": "./assert-shim.js",

packages/ses/scripts/bundle.js

@@ -53,6 +53,30 @@ const main = async () => {
     ...bundleFilePaths.map(dest => write(dest, versionedBundle)),
     ...terseFilePaths.map(dest => write(dest, terse)),
   ]);
+
+  // When importing types from a CJS package, TS v5.5+ considers the "module"
+  // field in `ses`' `package.json`, so any .d.ts file is considered to be "ESM
+  // types" (I'm sure this makes sense if you think hard enojugh about it; let
+  // us know if it does). For CJS, we need to provide a `.d.cts` file instead.
+  // It's unclear if this file can be identical to the original in _all_ cases,
+  // or just ours. I imagine ES-specific types (e.g., `import.meta`) would break
+  // in CJS, but generally consumers have `skipLibCheck` enabled, so ¯\_(ツ)_/¯
+
+  // Also: this operation is in this script for portability's sake.
+
+  /** The "ESM types" */
+  const sourceDTS = /** @type {string} */ (
+    packageJson.exports['.'].import.types
+  );
+  /** The "CJS types" */
+  const destDTS = /** @type {string} */ (
+    packageJson.exports['.'].require.types
+  );
+  await fs.promises.copyFile(
+    fileURLToPath(new URL(sourceDTS, root)),
+    fileURLToPath(new URL(destDTS, root)),
+  );
+  console.log(`Copied ${sourceDTS} to ${destDTS}`);
 };
 
 main().catch(err => {