Add /version slash command across CLI, gateway, TUI, and desktop.

Surfaces Hermes Agent version info on demand without leaving chat; works mid-run like /help and /update.

apps/desktop/src/lib/desktop-slash-commands.test.ts

@@ -15,6 +15,7 @@ describe('desktop slash command curation', () => {
     expect(isDesktopSlashSuggestion('/branch')).toBe(true)
     expect(isDesktopSlashSuggestion('/skin')).toBe(true)
     expect(isDesktopSlashSuggestion('/usage')).toBe(true)
+    expect(isDesktopSlashSuggestion('/version')).toBe(true)
     expect(isDesktopSlashSuggestion('/yolo')).toBe(true)
     expect(isDesktopSlashCommand('/yolo')).toBe(true)
   })

apps/desktop/src/lib/desktop-slash-commands.ts

@@ -43,6 +43,7 @@ const DESKTOP_COMMAND_META = [
   ['/title', 'Rename the current session'],
   ['/undo', 'Remove the last user/assistant exchange'],
   ['/usage', 'Show token usage for this session'],
+  ['/version', 'Show Hermes Agent version'],
   ['/yolo', 'Toggle YOLO — auto-approve dangerous commands']
 ] as const