F9: smoke checklist + performance budgets in CI

- docs/SMOKE.md: the F9 capability checklist — every carried-over harness
  capability mapped to at least one automated case (test target) or a
  manual probe with its observable, per the PRD acceptance rule.
- scripts/bench.sh: enforces both PRD performance budgets and fails CI on
  a miss — `kigi --version` p95 <= 50ms via hyperfine, and TUI first
  frame <= 300ms measured through the pty harness (real vt100 emulator
  answering terminal queries) via the new scripts/first-frame.scenario.json.
  Local run: p95 10.1ms, first frame 134ms.
- pty harness: StepOutcome gains elapsed_ms (stamped per step by the
  scripted runner) — a leading wait_for_text step's elapsed IS the
  spawn-to-first-paint latency the budget reads.
- CI: new `perf` job (macOS + Linux) building the release binaries and
  running scripts/bench.sh.

scripts/bench.sh

@@ -0,0 +1,64 @@
+#!/usr/bin/env bash
+# Performance budgets (PRD §7.3, enforced in CI from M2):
+#   1. `kigi --version` p95 ≤ 50 ms (hyperfine)
+#   2. TUI first frame ≤ 300 ms (PTY probe: spawn → first welcome paint)
+#
+# Usage: scripts/bench.sh [path-to-kigi-binary]
+# Defaults to target/release/kigi. Exits non-zero on any budget miss.
+set -euo pipefail
+
+KIGI_BIN="${1:-target/release/kigi}"
+VERSION_P95_BUDGET_MS=50
+FIRST_FRAME_BUDGET_MS=300
+
+if [[ ! -x "$KIGI_BIN" ]]; then
+    echo "error: kigi binary not found at $KIGI_BIN (build with: cargo build --release -p kigi-bin)" >&2
+    exit 2
+fi
+
+echo "── budget 1: '$KIGI_BIN --version' p95 ≤ ${VERSION_P95_BUDGET_MS}ms ──"
+json=$(mktemp)
+hyperfine --warmup 3 --runs 30 --export-json "$json" "$KIGI_BIN --version" >/dev/null
+p95_ms=$(python3 - "$json" <<'PY'
+import json, sys, statistics
+times = json.load(open(sys.argv[1]))["results"][0]["times"]
+qs = statistics.quantiles(times, n=20)  # qs[18] = p95
+print(f"{qs[18] * 1000:.1f}")
+PY
+)
+rm -f "$json"
+echo "p95 = ${p95_ms}ms"
+awk -v p="$p95_ms" -v b="$VERSION_P95_BUDGET_MS" 'BEGIN { exit !(p <= b) }' || {
+    echo "FAIL: --version p95 ${p95_ms}ms exceeds ${VERSION_P95_BUDGET_MS}ms" >&2
+    exit 1
+}
+
+echo "── budget 2: TUI first frame ≤ ${FIRST_FRAME_BUDGET_MS}ms ──"
+# Measured through the pty harness (real vt100 emulator answering terminal
+# queries): the leading wait_for_text step's elapsed_ms IS spawn → first
+# painted welcome frame. See scripts/first-frame.scenario.json.
+PTY_SCENARIO="${PTY_SCENARIO:-target/release/pty-scenario}"
+if [[ ! -x "$PTY_SCENARIO" ]]; then
+    echo "error: pty-scenario not found at $PTY_SCENARIO (build with: cargo build --release -p kigi-pager-pty-harness --bin pty-scenario)" >&2
+    exit 2
+fi
+artifacts=$(mktemp -d)
+report=$("$PTY_SCENARIO" \
+    --scenario scripts/first-frame.scenario.json \
+    --binary "$(cd "$(dirname "$KIGI_BIN")" && pwd)/$(basename "$KIGI_BIN")" \
+    --artifacts "$artifacts")
+rm -rf "$artifacts"
+first_ms=$(python3 - "$report" <<'PY'
+import json, sys
+d = json.loads(sys.argv[1][sys.argv[1].index("{"):])
+assert d["status"] == "passed", f"scenario failed: {d}"
+print(d["steps"][0]["elapsed_ms"])
+PY
+)
+echo "first frame = ${first_ms}ms"
+awk -v p="$first_ms" -v b="$FIRST_FRAME_BUDGET_MS" 'BEGIN { exit !(p <= b) }' || {
+    echo "FAIL: first frame ${first_ms}ms exceeds ${FIRST_FRAME_BUDGET_MS}ms" >&2
+    exit 1
+}
+
+echo "PASS: all performance budgets met"