docs: move verify to read-only docs and add agent guides

[ihsraham]

Summary

This PR standardizes the API reference documentation across all wallet modules and updates the Bitcoin, TON Gasless, and Tron Gas-Free modules to their latest beta versions (beta.5 and beta.4 respectively). It ensures consistent method signatures, return types (bigint), and properly documented inheritance for "Convenience Mode".

Changes

1. Bitcoin Module (wdk-wallet-btc) Updates (beta.5)

• Pluggable Transport: Added documentation and configuration support for injecting custom Electrum clients (e.g., ElectrumWs for browser support).
• New Classes: Added ElectrumWs and IElectrumClient to API Reference.
• Verify Method: Moved verify() to WalletAccountReadOnlyBtc while keeping it accessible in the main account class for convenience.
• Strict Typing: Updated all balance-related methods to return Promise<bigint>.
• Documentation Refinement: Improved API reference navigation by linking all major type definitions (e.g., BtcWalletConfig, IElectrumClient).

2. Gasless Modules Updates (beta.4)

• TON Gasless (wdk-wallet-ton-gasless):
  • Moved verify to WalletAccountTonGaslessReadOnly.
  • Updated return types to bigint.
• Tron Gas-Free (wdk-wallet-tron-gasfree):
  • Moved verify to WalletAccountTronGasfreeReadOnly.
  • Updated return types to bigint.

3. API Standardization & Fixes

• EVM Module:
  • Added approve() to WalletAccountEvm.
  • Added getAllowance() to WalletAccountReadOnlyEvm.
  • Restored duplicated inherited methods in api-reference.md for better developer experience ("Convenience Mode").
  • Updated configuration to use viem instead of outdated ethers v6 provider.
• Solana Module:
  • Added getTransactionReceipt() and verify() to proper classes.
  • Updated method signatures to match SDK.
• TON & Tron Modules:
  • Standardized verify, getTransactionReceipt, and bigint return types across documentation.
• Global Documentation:
  • Type Linking: Improved navigation in api-reference.md for all modules (EVM, Solana, TON, Tron, BTC, Gasless, Spark) by linking argument/return types to their definitions.

Verification

• Runtime Verification: Created verification environments for BTC, Gasless, and other chains to inspect .d.ts files and confirm method signatures/locations.
• Type Checking: Verified that number return types were updated to bigint where appropriate.