refactor(ext/node): consolidate node:fs (part 9)

Inline `_fs_read.ts`, `_fs_readdir.ts`, `_fs_readFile.ts`, and
`_fs_readlink.ts` into the main `fs.ts` module, following the same
pattern as parts 1-8. Update imports in `promises.ts`, `_fs_glob.ts`,
and `cp_sync.ts` to reference the consolidated location.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: bartlomieju

ext/node/lib.rs

@@ -386,10 +386,6 @@ deno_core::extension!(deno_node,
     "_fs/_fs_glob.ts",
     "_fs/_fs_lstat.ts",
     "_fs/_fs_lutimes.ts",
-    "_fs/_fs_read.ts",
-    "_fs/_fs_readdir.ts",
-    "_fs/_fs_readFile.ts",
-    "_fs/_fs_readlink.ts",
     "_next_tick.ts",
     "_process/exiting.ts",
     "_process/process.ts",

ext/node/polyfills/_fs/_fs_glob.ts

@@ -13,10 +13,7 @@ import { isMacOS, isWindows } from "ext:deno_node/_util/os.ts";
 import { kEmptyObject } from "ext:deno_node/internal/util.mjs";
 import process from "node:process";
 
-import {
-  readdirPromise as readdir,
-  readdirSync,
-} from "ext:deno_node/_fs/_fs_readdir.ts";
+import { readdirPromise as readdir, readdirSync } from "node:fs";
 import {
   lstatPromise as lstat,
   lstatSync,