- Added `pi-ast` as a new crate with public `language`, `ops`, and `summary` modules and exported `SupportLang`.
- Added AST summary and rewrite APIs in `pi-ast`, including language inference, overlap-safe edits, and span normalization.
- Added `pi-shell` crate with new `Shell` and cross-platform `Process` APIs, session execution, and cancellation-aware runs.
- Updated `pi-natives` to use shared `pi_ast`/`pi_shell` APIs, switched to local path deps, and moved minimizer assets to `pi-shell`.
can1357