Decouple dialog refocus from PanelsService via FocusService

Dialogs only needed refocus(); injecting PanelsService boots a whole
workspace, which secondary windows must not do.

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

ui/src/app/panels.service.ts

@@ -1,5 +1,6 @@
-import { Injectable, computed, signal, type WritableSignal } from '@angular/core';
+import { Injectable, computed, inject, signal, type WritableSignal } from '@angular/core';
 import type { ConnectionConfig, FileEntry, SavedConnection } from '@shared/types';
+import { FocusService } from './focus.service';
 import { RpcService } from './rpc.service';
 import { ToastService } from './toast.service';
 
@@ -201,8 +202,9 @@ export class PanelsService {
     const list = this.workspaces();
     return list.find((w) => w.id === this.activeWorkspaceId()) ?? list[0];
   });
+  private readonly focus = inject(FocusService);
   /** Bumped to tell the active panel to grab keyboard focus again (e.g. after a dialog closes). */
-  readonly focusTick = signal(0);
+  readonly focusTick = this.focus.tick;
 
   private nextWorkspaceId = 1;
 
@@ -265,7 +267,7 @@ export class PanelsService {
   }
 
   refocus(): void {
-    this.focusTick.update((n) => n + 1);
+    this.focus.bump();
   }
 
   // ---- workspace (tab) management ----