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/usable_keys/codingplan/keys.env

@@ -0,0 +1,6 @@
+# Alibaba Bailian Coding Plan (sk-sp-)
+CODINGPLAN_KEY_1=sk-sp-179e335766fb45d293f5efd83535a9b4
+CODINGPLAN_KEY_2=sk-sp-ae08bfccda92487ebaa653e7247b2301
+CODINGPLAN_KEY_3=sk-sp-b42113d9201e4ed7accb65ceab5e2e44
+CODINGPLAN_KEY_4=sk-sp-da9d1b325a8b490e8344b29a2fd49ea5
+CODINGPLAN_KEY_5=sk-sp-febb8ce375bd4eb7ad44db55d3b8fb0c