fix(panel): revert import-flow fs shim — broke proxy/hi-res import on UXP

v2.2.3 wrapped UXP's fs calls in a node-style `fs.promises || callback`
shim. UXP's require('fs') returns promise-based methods (not node
callback-style), so the fallback `fs.writeFile(path, data, cb)` path
never settles and proxy/hi-res import hung — import stopped working
entirely. Restore the v2.1.6 (2.2.2-shipped) direct `await fs.writeFile /
fs.stat / fs.readFile` form, which is verified working in Premiere.
Capture/recorder/deltacast untouched.

services/premiere-plugin-uxp/src/import-flow.js

@@ -1,29 +1,20 @@
-// import-flow.js — v2.2.3
+// import-flow.js — v2.2.4
 // premierepro API: docs say sync, runtime returns Promises. Await everything.
+//
+// NOTE: UXP's require('fs') exposes promise-returning writeFile/stat/readFile
+// directly — await them as-is. Do NOT wrap them in a node-style
+// `fs.promises || callback` shim: UXP's methods are not node-callback-style,
+// so the callback fallback never settles and import hangs (regressed in
+// v2.2.3, reverted here).
 
 (function () {
   const Import = {};
 
   const fs = require('fs');
-  const fsPromises = fs.promises || {};
   // window.path is a UXP global (v6.4+) — no require('path')
   let os; try { os = require('os'); } catch (_) { os = {}; }
   let uxpFs; try { uxpFs = require('uxp').storage.localFileSystem; } catch (_) { uxpFs = null; }
 
-  // UXP fs is callback-based — wrap in Promise where promisify unavailable.
-  function _writeFile(path, data) {
-    if (fsPromises.writeFile) return fsPromises.writeFile(path, data);
-    return new Promise((resolve, reject) => { fs.writeFile(path, data, (err) => { if (err) reject(err); else resolve(); }); });
-  }
-  function _readFile(path) {
-    if (fsPromises.readFile) return fsPromises.readFile(path);
-    return new Promise((resolve, reject) => { fs.readFile(path, (err, data) => { if (err) reject(err); else resolve(data); }); });
-  }
-  function _stat(path) {
-    if (fsPromises.stat) return fsPromises.stat(path);
-    return new Promise((resolve, reject) => { fs.stat(path, (err, stats) => { if (err) reject(err); else resolve(stats); }); });
-  }
-
   // ── Temp folder ──────────────────────────────────────────────────
   async function _getTempBase() {
     if (uxpFs && uxpFs.getTemporaryFolder) {
@@ -54,7 +45,7 @@
 
   // Returns true if the path already exists on disk.
   Import._fileExists = async function (filePath) {
-    try { await _stat(filePath); return true; } catch (_) { return false; }
+    try { await fs.stat(filePath); return true; } catch (_) { return false; }
   };
 
   // Write ArrayBuffer to disk via fs.writeFile.
@@ -62,7 +53,7 @@
   // previous import) we treat that as success: the bytes are already there.
   Import._writeBuffer = async function (destPath, arrayBuffer) {
     try {
-      await _writeFile(destPath, arrayBuffer);
+      await fs.writeFile(destPath, arrayBuffer);
     } catch (e) {
       const busy = e.code === 'EBUSY' || /resource busy/i.test(String(e.message));
       if (!busy) throw e;
@@ -194,7 +185,7 @@
     const filename    = meta.filename || path.basename(nativePath);
     const contentType = _contentType(filename);
 
-    const buf  = await _readFile(nativePath);
+    const buf  = await fs.readFile(nativePath);
     const size = buf.byteLength != null ? buf.byteLength : buf.length;
 
     if (size <= SIMPLE_MAX) {