feat(03-01): add 8 Tier 4 providers (Baichuan, StepFun, SenseTime, iFlytek, Tencent, SiliconFlow, 360AI, Kuaishou)

- SiliconFlow uses documented sk- prefix
- Other 7 keyword-only (no documented key format, avoids false positives)
- Completes PROV-04: 16 Tier 4 Chinese/regional providers

providers/360ai.yaml

@@ -0,0 +1,17 @@
+format_version: 1
+name: 360ai
+display_name: 360 AI Brain
+tier: 4
+last_verified: "2026-04-05"
+keywords:
+  - "360gpt"
+  - "QIHOO_API_KEY"
+  - "api.360.cn"
+  - "ai.360.com"
+  - "360-ai"
+verify:
+  method: GET
+  url: ""
+  headers: {}
+  valid_status: []
+  invalid_status: []