Extract SaveFilesToDisk/AppendFileRefs helpers into core package and wire up file handling for Cursor, Codex, OpenCode, Qoder, and iFlow. Files are saved to .cc-connect/attachments/ and paths are appended to the prompt so each CLI can read them with its built-in tools. Also refactors Claude Code to reuse the shared helper. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>