fix(hooks): add stack traces to hook errors, fix tools.ts theme bug

- HookError now includes optional stack field
- Hook error display shows stack trace in dim color below error message
- tools.ts: create SettingsListTheme using the theme passed to ctx.ui.custom()
  instead of using getSettingsListTheme() which depends on global theme

packages/coding-agent/examples/hooks/tools.ts

@@ -9,9 +9,8 @@
  * 2. Use /tools to open the tool selector
  */
 
-import { getSettingsListTheme } from "@mariozechner/pi-coding-agent";
 import type { HookAPI, HookContext } from "@mariozechner/pi-coding-agent/hooks";
-import { Container, type SettingItem, SettingsList } from "@mariozechner/pi-tui";
+import { Container, type SettingItem, SettingsList, type SettingsListTheme } from "@mariozechner/pi-tui";
 
 // State persisted to session
 interface ToolsState {
@@ -88,10 +87,20 @@ export default function toolsHook(pi: HookAPI) {
 					})(),
 				);
 
+				// Create theme for SettingsList using the passed theme
+				const settingsTheme: SettingsListTheme = {
+					label: (text: string, selected: boolean) => (selected ? theme.fg("accent", text) : text),
+					value: (text: string, selected: boolean) =>
+						selected ? theme.fg("accent", text) : theme.fg("muted", text),
+					description: (text: string) => theme.fg("dim", text),
+					cursor: theme.fg("accent", "→ "),
+					hint: (text: string) => theme.fg("dim", text),
+				};
+
 				const settingsList = new SettingsList(
 					items,
 					Math.min(items.length + 2, 15),
-					getSettingsListTheme(),
+					settingsTheme,
 					(id, newValue) => {
 						// Update enabled state and apply immediately
 						if (newValue === "enabled") {