fix: validate solana and evm private keys

[T1mn]

Pull Request | PR 提交

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• ## 📝 Description | 描述

English: Add stricter private key validation (EVM + Solana/Ed25519) and document accepted formats.
中文： 增强私钥校验（支持 EVM 与 Solana/Ed25519），并补充文档说明支持的输入格式。

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🎯 Type of Change | 变更类型

• 🐛 Bug fix | 修复 Bug
• ✨ New feature | 新功能
• 💥 Breaking change | 破坏性变更
• 📝 Documentation update | 文档更新
• 🎨 Code style update | 代码样式更新
• ♻️ Refactoring | 重构
• ⚡ Performance improvement | 性能优化
• ✅ Test update | 测试更新
• 🔧 Build/config change | 构建/配置变更
• 🔒 Security fix | 安全修复

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🔗 Related Issues | 相关 Issue

• Closes # | 关闭 #N/A
• Related to # | 相关 #N/A

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📋 Changes Made | 具体变更

English: ｜ 中文：

• Validate EVM private keys by length + hex content; accept optional 0x prefix.
• Add Solana/Ed25519 private key validation (Base58 or JSON array; 32-byte seed or 64-byte keypair with public-key
  consistency check).
• Document accepted private key formats in getting-started guides (EN/中文).
• Update Lighter cancel-stop logic to skip non-stop orders when order_type is provided.

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🧪 Testing | 测试

• Tested locally | 本地测试通过
• Tests pass | 测试通过
• Verified no existing functionality broke | 确认没有破坏现有功能（功能增强，未运行测试）

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✅ Checklist | 检查清单

Code Quality | 代码质量

• Code follows project style | 代码遵循项目风格
• Self-review completed | 已完成代码自查
• Comments added for complex logic | 已添加必要注释（不涉及复杂逻辑）

Documentation | 文档

• Updated relevant documentation | 已更新相关文档

Git

• Commits follow conventional format | 提交遵循 Conventional Commits 格式
• Rebased on latest dev branch | 已 rebase 到最新 dev 分支
• No merge conflicts | 无合并冲突

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📚 Additional Notes | 补充说明

English: Tests were not run due to module cache permission and proxy restrictions in the environment.
中文： 受环境模块缓存权限与代理限制影响，未运行测试。

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