Add llm-provider-billing skill: DeepSeek balance query

llm-provider-billing/scripts/deepseek-balance.sh

@@ -0,0 +1,18 @@
+#!/usr/bin/env bash
+# DeepSeek 余额实时查询 — 自动从 ~/.hermes/.env 读 key，无需手动 export
+# 用法: bash deepseek-balance.sh  (或 chmod +x 后直接执行)
+set -euo pipefail
+
+ENV_FILE="$HOME/.hermes/.env"
+KEY=$(grep '^DEEPSEEK_API_KEY=' "$ENV_FILE" 2>/dev/null | cut -d= -f2- | tr -d '"' | tr -d "'")
+
+if [ -z "$KEY" ]; then
+  echo "❌ 未在 $ENV_FILE 找到 DEEPSEEK_API_KEY" >&2
+  exit 1
+fi
+
+echo "🔍 查询 DeepSeek 余额 ..." >&2
+curl -s --max-time 20 https://api.deepseek.com/user/balance \
+  -H "Accept: application/json" \
+  -H "Authorization: Bearer $KEY"
+echo