fix: improve transaction compatibility and harden Stellar tools validation

[Feyzanur25]

Summary

This PR improves transaction signing compatibility, TypeScript safety, and the overall reliability of multiple Stellar tools within AgentKit.

Changes

Transaction Handling

• Improved transaction/XDR handling to ensure compatibility with newer Stellar SDK versions
• Replaced outdated patterns with a unified and safer transaction building approach
• Added validation for required parameters such as txXDR and networkPassphrase

Environment Validation

• Added runtime validation for STELLAR_PRIVATE_KEY and STELLAR_PUBLIC_KEY
• Removed unsafe non-null assertions (!) on environment variables
• Improved error messages for missing configuration

Bridge Tool Improvements

• Cleaned up duplicate and unused imports from the Stellar SDK
• Simplified keypair usage to avoid redundant creation
• Improved Soroban restore transaction handling
• Improved overall readability and maintainability

Liquidity Contract Tool Fixes

• Fixed TypeScript errors caused by checking truthiness on void return values
• Improved input validation for deposit, swap, withdraw, and reserve actions
• Refactored schema typing using z.infer<typeof schema>
• Improved response consistency and control flow

Staking Contract Tool Fixes

• Fixed incorrect handling of void return values in contract calls
• Improved validation for initialize, stake, unstake, and claim flows
• Simplified execution flow and success responses
• Removed unsafe any usage in error handling

TypeScript & Code Quality

• Replaced any with safer unknown error handling patterns
• Improved type safety and schema consistency
• Fixed invalid TypeScript typing issues
• Cleaned up code structure for better maintainability

Technical Impact

• Ensures compatibility with modern Stellar SDK versions
• Prevents runtime crashes caused by missing environment variables
• Improves TypeScript correctness and developer experience
• Strengthens reliability of bridge, staking, and liquidity tools
• Makes the codebase more production-ready and maintainable

Notes

This PR focuses on improving both runtime safety and developer experience while aligning the codebase with current best practices for Stellar and TypeScript-based tooling.

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Summary by cubic

Improves Stellar transaction signing and tool reliability with stronger runtime validation and a unified transaction builder. Adds AgentClient export and ensures compatibility with newer Stellar SDK versions.

• New Features

  • Added buildTransaction utility (with XDR support) to standardize fees, timeouts, and memos across tools; includes tests.
  • Exported AgentClient from index to simplify usage.

• Bug Fixes

  • Hardened signing: validate STELLAR_PRIVATE_KEY, txXDR, and networkPassphrase; switch to Transaction.fromXDR for safer parsing.
  • Enforced env checks for STELLAR_PUBLIC_KEY and STELLAR_PRIVATE_KEY to prevent runtime crashes.
  • Bridge tool cleanup and Soroban restore improvements; now uses the unified builder for consistent transactions.
  • Liquidity tool: fixed void handling, tightened input schemas (zod), and clarified control flow and responses.
  • Staking tool: corrected void handling, improved validation for initialize/stake/unstake/claim flows, and removed unsafe any.
  • General TypeScript safety improvements and cleanup for maintainability.

^{Written for commit 2da0744. Summary will update on new commits.}

[cubic-dev-ai]

No issues found across 3000 files

Note: This PR contains a large number of files. cubic only reviews up to 75 files per PR, so some files may not have been reviewed.