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/xunfei/dead.txt

@@ -0,0 +1,2 @@
+53656c1198a1a9c263fcdbce222f6f5e:Zjc2YWFmNTBjYTBkYWIwZTk4NmFhZmIx|https://github.com/tiandiyiqi/hermes-config/blob/95c2b68561ed19ec1644b5fee45c83971b505725/config.yaml|401 unauthorized
+704f582f9dcced4ae73a34baf7f0dc5d:OTZmZjYyOGJjNjExNDUxNmUzNmU4YWE2|https://github.com/Lyn-Lyn10/kddcup2016-data-agent/blob/06a2bb6eda2cb1f5dee31a049dc34aeb14fc63d7/configs/egmc_public_benchmark.yaml|401 unauthorized