Revert: all refactor commits migrating from Bun.file() to Filesystem module

packages/opencode/src/util/filesystem.ts

@@ -1,10 +1,8 @@
-import { chmod, mkdir, readFile, writeFile } from "fs/promises"
-import { createWriteStream, existsSync, statSync } from "fs"
+import { mkdir, readFile, writeFile } from "fs/promises"
+import { existsSync, statSync } from "fs"
 import { lookup } from "mime-types"
 import { realpathSync } from "fs"
 import { dirname, join, relative } from "path"
-import { Readable } from "stream"
-import { pipeline } from "stream/promises"
 
 export namespace Filesystem {
   // Fast sync version for metadata checks
@@ -70,25 +68,6 @@ export namespace Filesystem {
     return write(p, JSON.stringify(data, null, 2), mode)
   }
 
-  export async function writeStream(
-    p: string,
-    stream: ReadableStream<Uint8Array> | Readable,
-    mode?: number,
-  ): Promise<void> {
-    const dir = dirname(p)
-    if (!existsSync(dir)) {
-      await mkdir(dir, { recursive: true })
-    }
-
-    const nodeStream = stream instanceof ReadableStream ? Readable.fromWeb(stream as any) : stream
-    const writeStream = createWriteStream(p)
-    await pipeline(nodeStream, writeStream)
-
-    if (mode) {
-      await chmod(p, mode)
-    }
-  }
-
   export function mimeType(p: string): string {
     return lookup(p) || "application/octet-stream"
   }