Add LLM key-hunter toolkit, vault, and skill

- tools/scripts/llm-key-hunter: GitHub leak hunting pipeline (hunt_*,
  pivot miner, two-layer verify/content caches, per-provider verification)
- usable_keys: verified key vault across 12 providers (deepseek, minimax,
  volcanoark, longcat, codingplan, zhipu free-tier, mimo, siliconflow, etc.)
- .grok/skills/llm-key-hunter: operator skill for the hunt/verify/vault flow
- NewAPI channel import scripts and CDP capture helpers
- Result verdict buckets (excluding multi-GB blob caches and dedup dumps)

tools/scripts/llm-key-hunter/results/deepseek_v2/usable.txt

@@ -0,0 +1,5 @@
+sk-283b965c14624d50992f4d602ffe6bd9|https://github.com/qidu/model_proxy_v3/blob/84aeed1ff3dd48806f7514b5cbc08d54e107cc1e/testcases/06_integration/integration.test.js|balance: ¥0.5000 CNY
+sk-2c3f1f58031b4b86afdb6a8192ea02e2|https://github.com/answers111/alpha-research/blob/e6d64542ff2b87f75108b229d1a68da024a56f5a/configs/default_config.yaml|balance: ¥43.8200 CNY
+sk-6f66664876aa4e6c9fdf81deb35b9eca|https://github.com/ncsound919/Hemp-OS/blob/7f8cf731e6bd86375736b72cbee48caa8b7044e3/scripts/mass-scrape-v2.ts|balance: ¥1.4200 USD
+sk-715b3ab9c6eb47f3bf8baba393b63c35|https://github.com/GC-SHIRO/SCCA/blob/5573dab1712cf8e5796003014a86cee30a40e805/.scca/config.json|balance: ¥9.5000 CNY
+sk-f472f8cf87654d27aae3613f2b5c3a19|https://github.com/ycf-76/agentEdu/blob/4703799e080dcaaa20c96ab23bb79ef294e0641c/backend/app/core/config.py|balance: ¥2.6100 CNY