vfs: add archive provider backed by ZipBuffer/ZipFile

Adds an ArchiveProvider to node:vfs that mounts a ZipBuffer or ZipFile as
a virtual file system, built on the writable ZipBuffer/ZipFile support
added to node:zlib. provider.readonly reflects the underlying archive's
own writability.

Directories are recognized both explicitly (an entry name ending in /)
and implicitly (any entry name starting with "<dir>/"). Since a ZIP
member can't be edited or read in place, writes are buffered in memory
and only committed - as a new archive entry - when the file handle is
closed.

Every method has a synchronous counterpart backed by ZipBuffer/ZipFile's
own synchronous surface, documented as event-loop-blocking like the rest
of node:vfs's providers.

Author: pipobscure

doc/api/vfs.md

@@ -304,6 +304,55 @@ added: v26.4.0
 
 The resolved absolute path used as the root.
 
+## Class: `ArchiveProvider`
+
+<!-- YAML
+added: REPLACEME
+-->
+
+A provider that exposes the entries of a ZIP archive - either a
+[`zlib.ZipBuffer`][] (in memory) or a [`zlib.ZipFile`][] (on disk) - through
+the VFS API. `provider.readonly` reflects the archive's own
+[`zipFile.writable`][] flag: a `ZipBuffer` is always writable, and a
+`ZipFile` is writable only when opened with `{ writable: true }`.
+
+Directories are recognized both explicitly (an entry whose name ends in `/`)
+and implicitly (any entry name starting with `"<dir>/"`). `readdir()` does
+not support `{ recursive: true }`. Because a ZIP member cannot be edited or
+read in place - only fully written or fully decompressed - a file opened for
+writing only commits its content (as a new archive entry) when the handle is
+closed.
+
+Every method has a synchronous counterpart (`openSync()`, `statSync()`,
+`readdirSync()`, and so on), backed by the equally complete synchronous
+surface [`zlib.ZipBuffer`][]/[`zlib.ZipFile`][] expose. As with those, the
+synchronous methods here block the Node.js event loop and further JavaScript
+execution until the operation - including any deflate/inflate pass -
+completes.
+
+```cjs
+const vfs = require('node:vfs');
+const zlib = require('node:zlib');
+const { readFileSync } = require('node:fs');
+
+async function main() {
+  const zip = new zlib.ZipBuffer(readFileSync('archive.zip'));
+  const archiveVfs = vfs.create(new vfs.ArchiveProvider(zip));
+
+  console.log(await archiveVfs.promises.readdir('/'));
+  await archiveVfs.promises.writeFile('/new.txt', 'hello');
+}
+main();
+```
+
+### `new ArchiveProvider(source)`
+
+<!-- YAML
+added: REPLACEME
+-->
+
+* `source` {zlib.ZipBuffer|zlib.ZipFile} An already-open archive.
+
 ## Implementation details
 
 ### `Stats` objects
@@ -318,10 +367,14 @@ fields use synthetic but stable values:
 * `blocks` is `Math.ceil(size / 512)`.
 * Times default to the moment the entry was created/last modified.
 
+[`ArchiveProvider`]: #class-archiveprovider
 [`MemoryProvider`]: #class-memoryprovider
 [`RealFSProvider`]: #class-realfsprovider
 [`VirtualFileSystem`]: #class-virtualfilesystem
 [`VirtualProvider`]: #class-virtualprovider
 [`fs.BigIntStats`]: fs.md#class-fsbigintstats
 [`fs.Stats`]: fs.md#class-fsstats
 [`node:fs`]: fs.md
+[`zipFile.writable`]: zlib.md#zipfilewritable
+[`zlib.ZipBuffer`]: zlib.md#class-zlibzipbuffer
+[`zlib.ZipFile`]: zlib.md#class-zlibzipfile