fix(tui): restore prompt rendering on startup (#498)

* fix(tui): restore prompt rendering on startup

* test(tui): document render-time command split

* fix(tui): reduce ghostty prompt repaint scope

src/state/pluginCommandsStore.ts

@@ -0,0 +1,13 @@
+import type { Command } from '../commands.js'
+import { createStore } from './store.js'
+
+const pluginCommandsStore = createStore<Command[]>([])
+
+export const getPluginCommandsState = (): Command[] =>
+  pluginCommandsStore.getState()
+
+export const subscribePluginCommands = pluginCommandsStore.subscribe
+
+export function setPluginCommandsState(commands: Command[]): void {
+  pluginCommandsStore.setState(() => [...commands])
+}