Make workspace shell reads usable as direct chat-model input without changing the PTY or cursor model. This adds optional plain rendering and idle-window batching across CLI, SDK, and MCP while keeping raw reads backward-compatible.
Implement the rendering and wait-for-idle logic in the manager layer so the existing guest/backend shell transport stays unchanged. The new helper strips ANSI and other terminal control noise, handles carriage-return overwrite and backspace, and preserves raw cursor semantics even when plain output is requested.
Refresh the stable shell docs/examples to recommend --plain --wait-for-idle-ms 300, mark the 3.5.0 roadmap milestone done, and bump the package/catalog version to 3.5.0.
Validation: uv lock; UV_CACHE_DIR=.uv-cache make check; UV_CACHE_DIR=.uv-cache make dist-check; real guest-backed Firecracker smoke covering shell open/write/read with ANSI plus delayed output.
