feat(shell): enable PTY by default and various enhancements

### Shell & Interactive Terminal Improvements
- PTY shell is now enabled by default instead of disabled
- Improved shell output rendering, process termination, and added fallback warning
- Background commands now properly capture subprocess PIDs on non-Windows

### Coding Plan Improvements
- Simplified auth message, added /model tip, improved system info display
- Reordered model list to prioritize glm-5, kimi-k2.5, MiniMax-M2.5
- Model selection is now preserved when updating if the model still exists

### Other Changes
- Added shared symlink utility; debug logs now have latest alias
- Unknown settings warnings go to debug log instead of user-facing warnings
- Fixed subagent confirmation state detection
- Removed debug UI from AgentCreationWizard

Co-authored-by: Qwen-Coder <qwen-coder@alibabacloud.com>

packages/cli/src/config/settings.ts

@@ -14,6 +14,7 @@ import {
   QWEN_DIR,
   getErrorMessage,
   Storage,
+  createDebugLogger,
 } from '@qwen-code/qwen-code-core';
 import stripJsonComments from 'strip-json-comments';
 import { DefaultLight } from '../ui/themes/default-light.js';
@@ -32,6 +33,8 @@ import { customDeepMerge, type MergeableObject } from '../utils/deepMerge.js';
 import { updateSettingsFilePreservingFormat } from '../utils/commentJson.js';
 import { writeStderrLine } from '../utils/stdioHelpers.js';
 
+const debugLogger = createDebugLogger('SETTINGS');
+
 function getMergeStrategyForPath(path: string[]): MergeStrategy | undefined {
   let current: SettingDefinition | undefined = undefined;
   let currentSchema: SettingsSchema | undefined = getSettingsSchema();
@@ -564,7 +567,7 @@ function getSettingsFileKeyWarnings(
     );
   }
 
-  // Unknown top-level keys.
+  // Unknown top-level keys — log silently to debug output.
   const schemaKeys = new Set(Object.keys(getSettingsSchema()));
   for (const key of Object.keys(settings)) {
     if (key === SETTINGS_VERSION_KEY) {
@@ -577,8 +580,8 @@ function getSettingsFileKeyWarnings(
       continue;
     }
 
-    warnings.push(
-      `Warning: Unknown setting '${key}' will be ignored in ${settingsFilePath}.`,
+    debugLogger.warn(
+      `Unknown setting '${key}' will be ignored in ${settingsFilePath}.`,
     );
   }