- Implemented `rg` shell builtin using ripgrep libraries to enable file and directory searching.
- Added `RgSink` to handle output formatting, context, and vimgrep compatibility.
- Updated shell context and IO flags to support stdin as search input.
- Added integration tests for directory recursion, ignore filtering, and stdin handling.
- Introduced `pi-uutils-ctx` to manage thread-local I/O redirection, environment context, and path resolution for in-process utilities.
- Integrated a suite of vendored coreutils (cat, find, grep, head, ls, mkdir, mv, rm, sort, tail, uniq, wc) as shell builtins.
- Added infrastructure for command cancellation, streaming I/O, and locale-aware error reporting within the shell environment.
- Configured shell-side dispatch logic to route commands through the new utility context, enhancing performance and binary integration.
can1357