P1: typed RPC bridge + FileSystemProvider + dual-panel local browsing

- shared/types + shared/rpc: full wire contract (Result envelope, no exceptions cross the bridge)
- FileSystemProvider interface, LocalProvider, SessionRegistry with built-in 'local'
- walk.ts: provider-generic recursive walk + removeRecursive
- rpc-handlers wired into BrowserWindow; 10min request timeout for slow SFTP ops
- Angular: RpcService (Electroview bridge + plain-browser guard), PanelsService with
  signals-based PanelState (sort/cursor/selection), FilePanel component with
  keyboard nav (arrows/Space/Enter/Backspace/Tab), path bar, toasts
- verified: both panels listDir home over the bridge in the running app

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

ui/src/app/app.ts

@@ -1,16 +1,27 @@
-import { Component } from '@angular/core';
+import { Component, inject } from '@angular/core';
 import { NgIcon } from '@ng-icons/core';
 import { BRANDING } from '@shared/branding';
+import { FilePanel } from './file-panel/file-panel';
+import { RpcService } from './rpc.service';
+import { ToastService } from './toast.service';
 
 @Component({
   selector: 'app-root',
-  imports: [NgIcon],
+  imports: [NgIcon, FilePanel],
   templateUrl: './app.html',
 })
 export class App {
   readonly appName = BRANDING.appName;
+  readonly rpc = inject(RpcService);
+  readonly toast = inject(ToastService);
 
   constructor() {
     document.title = BRANDING.appName;
   }
+
+  toastIcon(kind: 'error' | 'info' | 'success'): string {
+    if (kind === 'error') return 'mynaXCircle';
+    if (kind === 'success') return 'mynaCheckCircle';
+    return 'mynaCheck';
+  }
 }