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/editor-window/editor-window.ts

@@ -10,7 +10,7 @@ import {
   viewChild,
 } from '@angular/core';
 import { NgIcon } from '@ng-icons/core';
-import { blockNativeContextMenu, EDITOR_CONTEXT, IS_MAC_CHROME } from '../platform';
+import { ALT_LABEL, blockNativeContextMenu, EDITOR_CONTEXT, IS_MAC_CHROME, MOD_LABEL } from '../platform';
 import { RpcService } from '../rpc.service';
 import { SettingsService } from '../settings.service';
 import { ToastService } from '../toast.service';
@@ -40,6 +40,8 @@ const DRAFT_DEBOUNCE_MS = 400;
 export class EditorWindow {
   readonly ctx = EDITOR_CONTEXT;
   readonly isMacChrome = IS_MAC_CHROME;
+  readonly modLabel = MOD_LABEL;
+  readonly altLabel = ALT_LABEL;
 
   readonly loading = signal(true);
   readonly loadError = signal<string | null>(null);