Windows compatibility pass (beta target)

External editor via cmd/start + exe picker; Permissions hidden for
Windows-local (chmod only flips read-only there); Explorer/Recycle Bin
wording; Ctrl vs Cmd shortcut labels; separator-aware path joins +
drive-root detection; drives list in the panel source picker; icon.ico
+ colored tray icon; icacls ACL on connections.json; README Windows
(beta) section with upstream known issues and a smoke-test checklist.
Runtime paths pending first boot on a real Windows machine.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

ui/src/app/panels.service.ts

@@ -2,7 +2,7 @@ import { Injectable, computed, inject, signal, type WritableSignal } from '@angu
 import type { ColumnKey, ConnectionConfig, FileEntry, SavedConnection } from '@shared/types';
 import { fileKind } from './file-icons';
 import { FocusService } from './focus.service';
-import { formatMode } from './format';
+import { formatMode, isRootPath, joinPath } from './format';
 import { RpcService } from './rpc.service';
 import { ToastService } from './toast.service';
 
@@ -73,8 +73,8 @@ export class PanelState {
       return cmp * dir;
     });
     const cwd = this.cwd();
-    if (cwd && cwd !== '/') {
-      list.unshift({ name: '..', path: `${cwd}/..`, type: 'dir', size: 0, mtime: 0, mode: 0 });
+    if (cwd && !isRootPath(cwd)) {
+      list.unshift({ name: '..', path: joinPath(cwd, '..'), type: 'dir', size: 0, mtime: 0, mode: 0 });
     }
     return list;
   });
@@ -144,7 +144,7 @@ export class PanelState {
 
   up(): void {
     if (!this.cwd()) return;
-    void this.load(`${this.cwd()}/..`);
+    void this.load(joinPath(this.cwd(), '..'));
   }
 
   /** Update the filter and park the cursor on the first real match. */