Document Windows Terminal Ctrl+V workaround for WSL clipboard paste #19500

Description\nWhen running OpenCode in WSL via Windows Terminal, can be intercepted by the terminal before OpenCode receives clipboard-related signals. In this setup, users can see inconsistent paste behavior (text may work while image paste does not).\n\n### Plugins\nN/A\n\n### OpenCode version\n1.3.3\n\n### Steps to reproduce\n1. Run OpenCode inside WSL2 Ubuntu 24.04 from Windows Terminal.\n2. Keep default terminal paste behavior.\n3. Try pasting both plain text and clipboard images into the TUI input.\n4. Observe inconsistent behavior depending on how terminal paste is handled.\n\n### Screenshot and/or share link\nN/A\n\n### Operating System\nWSL2 Ubuntu 24.04 on Windows 11\n\n### Terminal\nWindows Terminal