fix(ui): take the agentic turns default from DEFAULT_AGENTIC_CONFIG (#30582)

The registry hard-coded 10 for AGENTIC_MAX_TURNS while DEFAULT_AGENTIC_CONFIG
said 100. The registry seeds SETTING_CONFIG_DEFAULT, so the loop's
`|| DEFAULT_AGENTIC_CONFIG.maxTurns` fallback never fires and users got 10
turns. Reference the shared constant, as the adjacent MCP timeout does.

Assisted by: llama-ui (ggml-org/Qwen3.8-Flash-Next:IQ4_NL)

tools/ui/src/lib/constants/settings.constants.ts

@@ -1,3 +1,4 @@
+import { DEFAULT_AGENTIC_CONFIG } from './agentic.constants';
 import { CLI_FLAGS } from './cli-flags.constants';
 import { DEFAULT_MCP_CONFIG } from './mcp.constants';
 import { SETTINGS_KEYS } from './settings-keys.constants';
@@ -351,7 +352,7 @@ export const SETTINGS_REGISTRY: SettingsSectionEntry[] = [
 		icon: ListRestart,
 		settings: [
 			{
-				defaultValue: 10,
+				defaultValue: DEFAULT_AGENTIC_CONFIG.maxTurns,
 				help: 'Maximum number of tool execution cycles before stopping (prevents infinite loops).',
 				isPositiveInteger: true,
 				key: SETTINGS_KEYS.AGENTIC_MAX_TURNS,

tools/ui/tests/unit/agentic-max-turns-default.test.ts

@@ -0,0 +1,18 @@
+import { DEFAULT_AGENTIC_CONFIG, SETTINGS_KEYS } from '$lib/constants';
+import { describe, expect, it } from 'vitest';
+
+/**
+ * The registry `defaultValue` is the effective default: the store seeds its
+ * config from SETTING_CONFIG_DEFAULT, so the loop's
+ * `Number(setting) || DEFAULT_AGENTIC_CONFIG.maxTurns` fallback never fires.
+ * Once these disagreed (10 vs 100) and the loop silently stopped early.
+ */
+describe('AGENTIC_MAX_TURNS default value', () => {
+	it('sources the settings default from DEFAULT_AGENTIC_CONFIG.maxTurns', async () => {
+		const { SETTING_CONFIG_DEFAULT } = await import('$lib/constants');
+
+		expect(SETTING_CONFIG_DEFAULT[SETTINGS_KEYS.AGENTIC_MAX_TURNS]).toBe(
+			DEFAULT_AGENTIC_CONFIG.maxTurns
+		);
+	}, 15000);
+});