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/src/core/hooks/runner.ts

@@ -410,10 +410,12 @@ export class HookRunner {
 					}
 				} catch (err) {
 					const message = err instanceof Error ? err.message : String(err);
+					const stack = err instanceof Error ? err.stack : undefined;
 					this.emitError({
 						hookPath: hook.path,
 						event: event.type,
 						error: message,
+						stack,
 					});
 				}
 			}
@@ -477,10 +479,12 @@ export class HookRunner {
 					}
 				} catch (err) {
 					const message = err instanceof Error ? err.message : String(err);
+					const stack = err instanceof Error ? err.stack : undefined;
 					this.emitError({
 						hookPath: hook.path,
 						event: "context",
 						error: message,
+						stack,
 					});
 				}
 			}
@@ -523,10 +527,12 @@ export class HookRunner {
 					}
 				} catch (err) {
 					const message = err instanceof Error ? err.message : String(err);
+					const stack = err instanceof Error ? err.stack : undefined;
 					this.emitError({
 						hookPath: hook.path,
 						event: "before_agent_start",
 						error: message,
+						stack,
 					});
 				}
 			}

packages/coding-agent/src/core/hooks/types.ts

@@ -911,4 +911,5 @@ export interface HookError {
 	hookPath: string;
 	event: string;
 	error: string;
+	stack?: string;
 }