docs: add JSDoc documentation to useConnect hook and requestRaw function

[Dark-Brain07]

Description

Added comprehensive JSDoc documentation to undocumented functions in the @stacks/connect and @stacks/connect-react packages to improve the developer experience and IDE support.

Changes

packages/connect/src/request.ts

• Added JSDoc to requestRaw with @param, @returns, @throws, and cross-reference to request via @link

packages/connect-react/src/react/hooks/use-connect.ts

• Added JSDoc to the useConnect hook with usage example
• Added JSDoc to all 7 returned action functions:
  • doContractCall - contract call transaction popup
  • doContractDeploy - contract deploy popup
  • doSTXTransfer - STX transfer popup
  • doProfileUpdate - profile update popup
  • doSignTransaction - sign pre-built transaction hex
  • sign - arbitrary message signing
  • signPsbt - PSBT signing

Motivation

The useConnect hook is the primary React integration point for Stacks wallets, but its functions had no documentation. Developers using useConnect had to read the source to understand what each function does and what parameters it accepts.

Testing

Documentation-only changes. No functional code was modified.