Publish harness and TUI open-source

initial sync from the monorepo

crates/codegen/xai-grok-pager-pty-harness/benches/pty_baselines/README.md

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+# PTY benchmark baselines
+
+Baselines are per-platform (macOS arm64 has very different timing from an
+Linux arm64 CI runner) and per-scenario. CI compares the current run
+against the matching platform file and fails if any scenario's p99 frame
+time grows by more than 15% (default; `--threshold` overrides).
+
+File naming: `<platform>.json` where `<platform>` matches the CI artifact
+arch name — `linux-x86_64`, `linux-aarch64`, `macos-aarch64`.
+
+## Producing a baseline
+
+Run the full bench suite on a quiet machine:
+
+```bash
+cargo run -p xai-grok-pager --release --bin pty-bench -- \
+  --all \
+  --write-baseline crates/codegen/xai-grok-pager-pty-harness/benches/pty_baselines/<platform>.json
+```
+
+## Overwriting after an intentional perf change
+
+A PR that intentionally shifts frame timing (either direction) must update
+the affected baselines. Include the `pty-bench` output from a clean run in
+the PR body so reviewers can sanity-check the new numbers.
+
+## First run
+
+Platform files are seeded on first CI run (see `pager-bench` job). Until
+then, `--baseline <missing-file>` will fail loudly with a clear error.