feat: add Bun.Archive API for creating and extracting tarballs (#25665)

## Summary

- Adds new `Bun.Archive` API for working with tar archives
- `Bun.Archive.from(data)` - Create archive from object, Blob,
TypedArray, or ArrayBuffer
- `Bun.Archive.write(path, data, compress?)` - Write archive to disk
(async)
- `archive.extract(path)` - Extract to directory, returns
`Promise<number>` (file count)
- `archive.blob(compress?)` - Get archive as Blob (async)
- `archive.bytes(compress?)` - Get archive as Uint8Array (async)

Key implementation details:
- Uses existing libarchive bindings for tarball creation/extraction via
`extractToDisk`
- Uses libdeflate for gzip compression
- Immediate byte copying for GC safety (no JSValue protection, no
`hasPendingActivity`)
- Async operations run on worker pool threads with proper VM reference
handling
- Growing memory buffer via `archive_write_open2` callbacks for
efficient tarball creation

## Test plan

- [x] 65 comprehensive tests covering:
  - Normal operations (create, extract, blob, bytes, write)
  - GC safety (unreferenced archives, mutation isolation)  
  - Error handling (invalid args, corrupted data, I/O errors)
- Edge cases (large files, many files, special characters, path
normalization)
  - Concurrent operations

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>
Co-authored-by: Dylan Conway <dylan.conway567@gmail.com>
Co-authored-by: Jarred Sumner <jarred@jarredsumner.com>

test/js/bun/archive-extract-leak-repro.ts

@@ -0,0 +1,33 @@
+// Minimal reproduction of memory leak in Bun.Archive.extract()
+// Run with: bun run test/js/bun/archive-extract-leak-repro.ts
+
+import { mkdtempSync, rmSync } from "fs";
+import { tmpdir } from "os";
+import { join } from "path";
+
+const dir = mkdtempSync(join(tmpdir(), "archive-leak-"));
+
+const files = {
+  "a.txt": "hello",
+  "b.txt": "world",
+};
+
+const archive = Bun.Archive.from(files);
+
+function formatMB(bytes: number) {
+  return (bytes / 1024 / 1024).toFixed(0) + " MB";
+}
+
+console.log("Extracting archive 10,000 times per round...\n");
+
+for (let round = 0; round < 20; round++) {
+  for (let i = 0; i < 10_000; i++) {
+    await archive.extract(dir);
+  }
+
+  Bun.gc(true);
+  const rss = process.memoryUsage.rss();
+  console.log(`Round ${round + 1}: RSS = ${formatMB(rss)}`);
+}
+
+rmSync(dir, { recursive: true });