fix: revert import.meta.dirname to __dirname for CJS output

PR1 emits CJS output (no "type": "module" yet), so import.meta
is not available. Revert to __dirname in browserScript.ts and
createServer.ts. Remove __esModule export from RollupPluginHTMLOptions.

Assisted-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: bennypowers

packages/browser-logs/src/browserScript.ts

@@ -4,10 +4,10 @@ import path from 'path';
 const REGEXP_SOURCE_MAP = /\/\/# sourceMappingURL=.*/;
 
 const serializeScript = fs
-  .readFileSync(path.resolve(import.meta.dirname, 'serialize.js'), 'utf-8')
+  .readFileSync(path.resolve(__dirname, 'serialize.js'), 'utf-8')
   .replace(REGEXP_SOURCE_MAP, '');
 const logUncaughtErrorsScript = fs
-  .readFileSync(path.resolve(import.meta.dirname, 'logUncaughtErrors.js'), 'utf-8')
+  .readFileSync(path.resolve(__dirname, 'logUncaughtErrors.js'), 'utf-8')
   .replace(REGEXP_SOURCE_MAP, '');
 
 /**

packages/dev-server-core/src/server/createServer.ts

@@ -68,7 +68,7 @@ export function createServer(
 
   let server: Server;
   if (cfg.http2) {
-    const dir = path.join(import.meta.dirname, '..');
+    const dir = path.join(__dirname, '..');
     const options = {
       key: fs.readFileSync(
         cfg.sslKey

packages/rollup-plugin-html/src/RollupPluginHTMLOptions.ts

@@ -1,8 +1,6 @@
 import type { OutputChunk, OutputOptions, OutputBundle } from 'rollup';
 import type { Attribute } from 'parse5';
 
-// Ensure this file is evaluated as an ES module
-export const __esModule = true;
 
 export interface InputHTMLOptions {
   /** The html source code. If set, overwrites path. */