Add native UI decision and testing workflow

scripts/ci.sh

@@ -0,0 +1,15 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+cargo fmt --all --check
+cargo clippy --workspace --all-targets --all-features -- -D warnings
+
+if command -v cargo-nextest >/dev/null 2>&1; then
+  cargo nextest run --workspace --all-features --profile "${NEXTEST_PROFILE:-default}"
+else
+  echo "cargo-nextest not installed; using cargo test" >&2
+  cargo test --workspace --all-features
+fi
+
+# nextest deliberately does not run doctests on stable Rust.
+cargo test --workspace --all-features --doc

scripts/watch.sh

@@ -0,0 +1,15 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+if command -v bacon >/dev/null 2>&1; then
+  exec bacon "$@"
+fi
+
+# Compatibility for developers who still have the now-dormant cargo-watch.
+if command -v cargo-watch >/dev/null 2>&1; then
+  exec cargo watch -x "check --workspace --all-targets --all-features" \
+    -x "test --workspace --all-features"
+fi
+
+echo "Install Bacon with: cargo install --locked bacon" >&2
+exit 127