added: profiling toolchain (py-spy, pyinstrument, pytest-benchmark, memray, snakeviz)

New `profile` optional-deps group, opt-in Pyinstrument ASGI middleware
gated by DECNET_PROFILE_REQUESTS, bench marker + tests/perf/ micro-benchmarks
for repository hot paths, and scripts/profile/ helpers for py-spy/cProfile/memray.

scripts/profile/cprofile-cli.sh

@@ -0,0 +1,17 @@
+#!/usr/bin/env bash
+# Run a `decnet` subcommand under cProfile and write a .prof file for snakeviz.
+# Usage: scripts/profile/cprofile-cli.sh services
+#        scripts/profile/cprofile-cli.sh status
+set -euo pipefail
+
+if [[ $# -lt 1 ]]; then
+    echo "Usage: $0 <decnet-subcommand> [args...]" >&2
+    exit 1
+fi
+
+OUT="${OUT:-profiles/cprofile-$(date +%s).prof}"
+mkdir -p "$(dirname "$OUT")"
+
+python -m cProfile -o "${OUT}" -m decnet.cli "$@"
+echo "Wrote ${OUT}"
+echo "View with: snakeviz ${OUT}"

scripts/profile/memray-api.sh

@@ -0,0 +1,15 @@
+#!/usr/bin/env bash
+# Run the DECNET API under memray to capture an allocation profile.
+# Stop with Ctrl-C; then render with `memray flamegraph <bin>`.
+set -euo pipefail
+
+HOST="${DECNET_API_HOST:-127.0.0.1}"
+PORT="${DECNET_API_PORT:-8000}"
+OUT="${OUT:-profiles/memray-$(date +%s).bin}"
+mkdir -p "$(dirname "$OUT")"
+
+echo "Starting uvicorn under memray -> ${OUT}"
+python -m memray run -o "${OUT}" -m uvicorn decnet.web.api:app \
+    --host "${HOST}" --port "${PORT}" --log-level warning
+
+echo "Render with: memray flamegraph ${OUT}"

scripts/profile/pyspy-attach.sh

@@ -0,0 +1,18 @@
+#!/usr/bin/env bash
+# Attach py-spy to the running DECNET uvicorn worker(s) and record a flamegraph.
+# Requires sudo on Linux because of kernel.yama.ptrace_scope=1 by default.
+set -euo pipefail
+
+DURATION="${DURATION:-30}"
+OUT="${OUT:-profiles/pyspy-$(date +%s).svg}"
+mkdir -p "$(dirname "$OUT")"
+
+PID="$(pgrep -f 'uvicorn decnet.web.api' | head -n 1 || true)"
+if [[ -z "${PID}" ]]; then
+    echo "No uvicorn worker found. Start the API first (e.g. 'decnet deploy ...')." >&2
+    exit 1
+fi
+
+echo "Attaching py-spy to PID ${PID} for ${DURATION}s -> ${OUT}"
+sudo py-spy record -o "${OUT}" -p "${PID}" -d "${DURATION}" --subprocesses
+echo "Wrote ${OUT}"