Describe the bug:
After upgrading from 2026.3.28 to 2026.4.5, Gateway startup time increased significantly due to provider validation during models.list.

Version comparison:

Logs (2026.4.5):

15:11:44+08:00 [gateway] ready (3 plugins, 2.4s)  ? Gateway itself starts fast
...
15:13:01+08:00 [ws] ? res ? chat.history 33773ms
15:13:01+08:00 [ws] ? res ? models.list 33676ms  ? This blocks startup

Configuration:

• 9 providers (bailian, deepseek, scnet, infinigence, etc.)
• 50+ models
• Config file: 114KB

Expected behavior:
Startup should remain fast regardless of provider count. Provider validation could be:

1. Lazy-loaded - validate on first use, not at startup
2. Parallel - check providers concurrently
3. Optional - a config flag to disable startup validation

Environment:

• Windows 10
• Node v24.14.0
• OpenClaw 2026.4.5