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/format.ts

@@ -0,0 +1,34 @@
+const SIZE_UNITS = ['B', 'KB', 'MB', 'GB', 'TB'];
+
+export function formatSize(bytes: number): string {
+  let value = bytes;
+  let unit = 0;
+  while (value >= 1024 && unit < SIZE_UNITS.length - 1) {
+    value /= 1024;
+    unit++;
+  }
+  return `${unit === 0 ? value : value.toFixed(1)} ${SIZE_UNITS[unit]}`;
+}
+
+const DATE_FORMAT = new Intl.DateTimeFormat(undefined, {
+  year: '2-digit',
+  month: '2-digit',
+  day: '2-digit',
+  hour: '2-digit',
+  minute: '2-digit',
+});
+
+export function formatDate(epochMs: number): string {
+  if (!epochMs) return '';
+  return DATE_FORMAT.format(new Date(epochMs));
+}
+
+/** 0o755 -> "rwxr-xr-x" */
+export function formatMode(mode: number): string {
+  const flags = 'rwxrwxrwx';
+  let out = '';
+  for (let i = 0; i < 9; i++) {
+    out += mode & (0o400 >> i) ? flags[i] : '-';
+  }
+  return out;
+}