Some Kata/microVM guest kernels (e.g. the CI runner's 6.18.x) are built
without CONFIG_PROC_CHILDREN, so /proc/<pid>/task/<tid>/children does not
exist. The Linux children() relied on it with no fallback, making
children()/live_descendants() return empty and silently turning shell
cancellation cleanup into a no-op inside such containers.
Fall back to scanning /proc and grouping by parent pid (the same primitive
the macOS path already uses) when no children file is readable; kernels
with the file keep the cheap per-task fast path. Also fixes
process::tests::descendants_includes_freshly_spawned_child under Kata CI.
- Applied #[must_use] annotations across minimizer and process APIs to flag ignored return values.
- Replaced direct serde_json field reads with typed Value helper calls in several filters.
- Simplified filter parsing with chained if-let guards, rfind checks, and related cleanup.
- Updated minimizer tests and fixtures to build outputs via write! and fmt::Write.
- Replaced macOS `Process::children` and `descendants` traversal with a one-shot `proc_listallpids` scan grouped by `pbi_ppid`, avoiding the broken self-query path in `proc_listchildpids`.
- Built `snapshot_all_pids` and `build_process_tree` helpers and updated descendant collection to walk that tree once, de-duplicating by PID in post-order.
- Added a Unix regression test that verified a freshly spawned child appears in `live_descendants`, preventing silent no-op cleanup on affected darwin kernels.
- Restricted pgid adoption in `select_termination_targets` to only descendants that are their own group leader, preventing inherited harness pgids from entering the kill set.
- Added `kill_process_group` guard to refuse signaling the harness's own process group as a last-line defense.
- Awaited the `bridge_chunks` drain handle after shell/execute completes to ensure all output chunks are flushed before the future resolves.
- Removed ~1,500 lines of platform-specific process code from pi-natives/ps.rs, delegating to pi_shell::process.
- Removed PTY execution support from pi-shell and pi-natives, including portable-pty dependency.
- Exposed terminate_tree and wait_for_exit as public methods on pi_shell::process::Process.
- 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