1.4.0: not_found, server-only response options, compression

- Server functions can return not_found: true to render the 404 page
  with status 404.
- Page components and window.__PAGE_PROPS__ (and HMR updates) only get
  props, query, url and error. response_options, redirect, cache settings
  and res_transform stay on the server, so cookies and private headers no
  longer end up in the HTML. BunextPageProps is narrowed to match
  (breaking for code that read server-only fields from component props).
- response_options headers go through a Headers object, so repeated
  headers such as several Set-Cookie survive.
- Redirects: status_code wins over permanent; response_options headers
  and res_transform apply to redirects too.
- Gzip for compressible text responses; compress: false to turn it off.
- Files the router matches but never bundles (.server.ts, __root,
  excluded paths and directories) return 404 instead of looping through
  dev rebuild retries.
- Missing public files return 404 rather than 403, so dotted page paths
  like /users/john.doe fall through to pages again.
- importFresh detects rewrites within the filesystem's mtime granularity.
- README: self-hosted React (not esm.sh), snake_case option names, static
  file serving, cache headers, the new options.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

dist/functions/server/cleanup-artifacts.js

@@ -2,7 +2,7 @@ import { log } from "../../utils/log";
 import path from "path";
 import grabDirNames from "../../utils/grab-dir-names";
 import { existsSync, readdirSync, statSync, unlinkSync } from "fs";
-const { ROOT_DIR, HYDRATION_DST_DIR, BUNX_CWD_MODULE_CACHE_DIR } = grabDirNames();
+const { ROOT_DIR } = grabDirNames();
 // esbuild's content hashes are 8-char base64-ish (e.g. `CMSI7VSQ`). Entry
 // outputs are `<dir>/<hash>.js` / `<dir>/<hash>.css`. Shared chunks are
 // `chunk-*.js` and MUST be kept: any current entry may still reference an
@@ -19,6 +19,7 @@ const ENTRY_HASH_FILE = /^[A-Za-z0-9]{8}\.(js|css)$/;
  * left untouched.
  */
 export default async function cleanupArtifacts({ paradigm }) {
+    const { HYDRATION_DST_DIR, BUNX_CWD_MODULE_CACHE_DIR } = grabDirNames();
     const is_hydration = paradigm === "hydration";
     const root_dir = is_hydration
         ? HYDRATION_DST_DIR