chore: simplified tx builder

[SWvheerden]

Description

New simpliefied tx builder

Summary by CodeRabbit

• New Features

  • New builder-based transaction flow with fee estimation, streamlined inputs/outputs, automatic change handling, and clearer one-shot finalization.
  • Simplified one-sided/stealth payment paths unified across wallet and gRPC.

• Breaking Changes

  • CLI: "SendMinotari" command removed.
  • FFI: wallet_send_transaction signature no longer accepts a one_sided flag — update callers.
  • gRPC: standard Mimblewimble sends rejected; use one-sided or stealth-address flows.
  • Public services/handles now require key-manager–specific types; integrations must be updated.

• Chores

  • Removed legacy protocol restart utilities, protocol streams, and related task APIs.